LAN8740A/LAN8740Ai Small Footprint MII/RMII 10/100 Energy Efficient Ethernet Transceiver with HP Auto-MDIX and flexPWR® Technology Highlights Key Benefits • Single-Chip Ethernet Physical Layer Transceiver • High-performance 10/100 Ethernet transceiver (PHY) - Compliant with IEEE802.3/802.3u (Fast Ethernet) • Compliant with Energy Efficient Ethernet 802.3az - Compliant with ISO 802-3/IEEE 802.3 • Cable diagnostic support (10BASE-T) - Compliant with Energy Efficient Ethernet IEEE • Wake on LAN (WoL) support 802.3az • Comprehensive flexPWR technology - Loop-back modes - Flexible power management architecture - Auto-negotiation - LVCMOS Variable I/O voltage range: +1.8 V to - Automatic polarity detection and correction +3.3 V - Link status change wake-up detection - Integrated 1.2 V regulator with disable feature - Vendor specific register functions • HP Auto-MDIX support - Supports both MII and the reduced pin count RMII • Small footprint 32-pin VQFN, RoHS-compliant interfaces package (5 x 5 x 0.9 mm height) • Power and I/Os • Deterministic 100Mb internal loopback latency - Various low power modes (MII Mode) - Integrated power-on reset circuit Target Applications - Two status LED outputs - May be used with a single 3.3 V supply • Set-Top Boxes • Additional Features • Networked Printers and Servers - Ability to use a low cost 25 MHz crystal for • Test Instrumentation reduced BOM • LAN on Motherboard • Packaging • Embedded Telecom Applications - 32-pin VQFN (5 x 5 mm), RoHS-compliant • Video Record/Playback Systems package with MII and RMII • Cable Modems/Routers • Environmental • DSL Modems/Routers - Commercial temperature range (0°C to +70°C) • Digital Video Recorders - Industrial temperature range (-40°C to +85°C) • IP and Video Phones • Wireless Access Points • Digital Televisions • Digital Media Adapters/Servers • Gaming Consoles • POE Applications (Refer to Microchip Application Note 17.18)  2013-2015 Microchip Technology Inc. DS00001987A-page 1

LAN8740A/LAN8740Ai TO OUR VALUED CUSTOMERS It is our intention to provide our valued customers with the best documentation possible to ensure successful use of your Microchip products. To this end, we will continue to improve our publications to better suit your needs. Our publications will be refined and enhanced as new volumes and updates are introduced. If you have any questions or comments regarding this publication, please contact the Marketing Communications Department via E-mail at docerrors@microchip.com. We welcome your feedback. Most Current Data Sheet To obtain the most up-to-date version of this data sheet, please register at our Worldwide Web site at: http://www.microchip.com You can determine the version of a data sheet by examining its literature number found on the bottom outside corner of any page. The last character of the literature number is the version number, (e.g., DS30000000A is version A of document DS30000000). Errata An errata sheet, describing minor operational differences from the data sheet and recommended workarounds, may exist for current devices. As device/documentation issues become known to us, we will publish an errata sheet. The errata will specify the revision of silicon and revision of document to which it applies. To determine if an errata sheet exists for a particular device, please check with one of the following: • Microchip’s Worldwide Web site: http://www.microchip.com • Your local Microchip sales office (see last page) When contacting a sales office, please specify which device, revision of silicon and data sheet (include -literature number) you are using. Customer Notification System Register on our web site at www.microchip.com to receive the most current information on all of our products. DS00001987A-page 2  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai Table of Contents 1.0 Introduction .....................................................................................................................................................................................4 2.0 Pin Description and Configuration ..................................................................................................................................................6 3.0 Functional Description ..................................................................................................................................................................17 4.0 Register Descriptions ....................................................................................................................................................................58 5.0 Operational Characteristics .........................................................................................................................................................113 6.0 Package Outline ..........................................................................................................................................................................127 Appendix A: Revision History ............................................................................................................................................................130 The Microchip Web Site ....................................................................................................................................................................133 Customer Change Notification Service .............................................................................................................................................133 Customer Support .............................................................................................................................................................................133 Product Identification System ...........................................................................................................................................................134  2013-2015 Microchip Technology Inc. DS00001987A-page 3

LAN8740A/LAN8740Ai 1.0 INTRODUCTION 1.1 General Terms and Conventions The following is a list of the general terms used throughout this document: BYTE 8 bits FIFO First In First Out buffer; often used for elasticity buffer MAC Media Access Controller MII Media Independent Interface RMII™ Reduced Media Independent Interface N/A Not Applicable X Indicates that a logic state is “don’t care” or undefined. RESERVED Refers to a reserved bit field or address. Unless otherwise noted, reserved bits must always be zero for write operations. Unless otherwise noted, values are not guaranteed when reading reserved bits. Unless otherwise noted, do not read or write to reserved addresses. SMI Serial Management Interface 1.2 General Description The LAN8740A/LAN8740Ai is a low-power 10BASE-T/100BASE-TX physical layer (PHY) transceiver with variable I/O voltage that is compliant with the IEEE 802.3, 802.3u, and 802.3az (Energy Efficient Ethernet) standards. Energy Effi- cient Ethernet (EEE) support results in significant power savings during low link utilizations. The LAN8740A/LAN8740Ai supports communication with an Ethernet MAC via a standard MII (IEEE 802.3u)/RMII inter- face. It contains a full-duplex 10-BASE-T/100BASE-TX transceiver and supports 10Mbps (10BASE-T) and 100 Mbps (100BASE-TX) operation. The LAN8740A/LAN8740Ai implements auto-negotiation to automatically determine the best possible speed and duplex mode of operation. HP Auto-MDIX support allows the use of direct connect or cross-over LAN cables. Integrated Wake on LAN (WoL) support provides a mechanism to trigger an interrupt upon reception of a perfect DA, broadcast, magic packet, or wakeup frame. The LAN8740A/LAN8740Ai supports both IEEE 802.3-2005 compliant and vendor-specific register functions. However, no register access is required for operation. The initial configuration may be selected via the configuration pins as described in Section 3.7, "Configuration Straps". Register-selectable configuration options may be used to further define the functionality of the transceiver. The LAN8740A/LAN8740Ai can be programmed to support wake-on-LAN at the physical layer, allowing detection of configurable Wake-up Frame and Magic packets. This feature allows filtering of packets at the PHY layer, without requir- ing MAC intervention. Additionally, the LAN8740A/LAN8740Ai supports cable diagnostics which allow the device to identify opens/shorts and their location on the cable via vendor-specific registers. Per IEEE 802.3-2005 standards, all digital interface pins are tolerant to 3.6 V. The device can be configured to operate on a single 3.3 V supply utilizing an integrated 3.3 V to 1.2 V linear regulator. The linear regulator may be optionally disabled, allowing usage of a high efficiency external regulator for lower system power dissipation. DS00001987A-page 4  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai The LAN8740A/LAN8740Ai is available in commercial (0°C to +70°C) and industrial (-40°C to +85°C) temperature range versions. A typical system application is shown in Figure 1-1. Figure 1-2 provides an internal block diagram of the device. FIGURE 1-1: SYSTEM BLOCK DIAGRAM 10/100 MII/ Ethernet RMII LAN8740A/ MDI Transformer RJ45 LAN8740Ai MAC Mode LED Crystal or Clock Oscillator FIGURE 1-2: ARCHITECTURAL OVERVIEW MODE[0:2] Mode Control HP Auto-MDIX Auto- 100M TX 100M TXP/TXN nRST Reset Control Negotiation Logic Transmitter RMIISEL Transmitter RXP/RXN TXD[0:3] SMI Management 10M TX 10M MDIX TXEN Control Logic Transmitter Control TXER XTAL1/CLKIN TXCLK PLL XTAL2 RXD[0:3] c gi RXDV Lo 100M RX DSP System: Analog-to- Interrupt nINT RXER MII Logic DataC Rloecckovery Digital Generator RXCLK MII/ WoL Equalizer 100M PLL LED1 R LEDs CRS Receiver LED2 COL/CRS_DV 10M RX Squeltch MDC Logic & Filters Central Bias RBIAS 10M PLL MDIO PHY Address PHYAD[0:2] Latches LAN8740A/LAN8740Ai  2013-2015 Microchip Technology Inc. DS00001987A-page 5

LAN8740A/LAN8740Ai 2.0 PIN DESCRIPTION AND CONFIGURATION FIGURE 2-1: 32-VQFN PIN ASSIGNMENTS (TOP VIEW) BIAS XP XN XP XN DD1A XDV XD3 R R R T T V R T 2 1 0 9 8 7 6 5 3 3 3 2 2 2 2 2 VDD2A 1 24 TXD2 LED2/nINT/nPME/nINTSEL 2 23 TXD1 LED1/nINT/nPME/REGOFF 3 22 TXD0 LAN8740A/ XTAL2 4 21 TXEN LAN8740Ai XTAL1/CLKIN 5 20 TXCLK VDDCR 6 19 nRST RXCLK/PHYAD1 7 18 nINT/TXER/TXD4 RXD3/PHYAD2 8 17 MDC 9 10 11 12 13 14 15 16 L 1 0 O 0 S 2 O SE DE DE DI AD CR DE DI MII MO MO VD HY MO M E/R D1/ D0/ 4/P DV/ PM RX RX XD S_ n R R 2/ R/ C D E L/ X X O R R C Note:Exposed pad (VSS) on bottom of package must be connected to ground. Note: When a lower case “n” is used at the beginning of the signal name, it indicates that the signal is active low. For example, nRST indicates that the reset signal is active low. Note: The buffer type for each signal is indicated in the BUFFER TYPE column. A description of the buffer types is provided in Section2.2. DS00001987A-page 6  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai TABLE 2-1: MII/RMII SIGNALS Num Pins Name Symbol Buffer Type Description 1 Transmit TXD0 VIS The MAC transmits data to the transceiver using Data 0 this signal in all modes. 1 Transmit TXD1 VIS The MAC transmits data to the transceiver using Data 1 this signal in all modes. 1 Transmit TXD2 VIS The MAC transmits data to the transceiver using Data 2 this signal in MII mode. (MII Mode) Note: This signal must be grounded in RMII mode. 1 Transmit TXD3 VIS The MAC transmits data to the transceiver using Data 3 this signal in MII mode. (MII Mode) Note: This signal must be grounded in RMII mode. 1 Interrupt Out- nINT VOD8 Active low interrupt output. Place an external resis- put (PU) tor pull-up to VDDIO. Note: The nINT signal can be optionally con- figured to output on the LED1 or LED2 pins. Refer to Section 3.6, "Interrupt Management" for additional details on device interrupts. Note: Refer to Section 3.8.1.6, "nINTSEL and LED2 Polarity Selection" for details on how the nINTSEL configuration strap is used to determine the function of this pin. Transmit Error TXER VIS When driven high, the 4B/5B encode process sub- (MII Mode) stitutes the Transmit Error code-group (/H/) for the encoded data word. This input is ignored in the 10BASE-T mode of operation. This signal is also used in EEE mode as TXER when TXEN=1, and as LPI when TXEN=0. Note: This signal is not used in RMII mode. Transmit TXD4 VIS In Symbol Interface (5B decoding) mode, this sig- Data 4 (PU) nal becomes the MII Transmit Data 4 line (the MSB (MII Mode) of the 5-bit symbol code-group). Note: This signal is not used in RMII mode. 1 Transmit TXEN VIS Indicates that valid transmission data is present on Enable (PD) TXD[3:0]. In RMII mode, only TXD[1:0] provide valid data. 1 Transmit Clock TXCLK VO8 Used to latch data from the MAC into the trans- (MII Mode) ceiver. • MII (100BASE-TX): 25 MHz • MII (10BASE-T): 2.5 MHz Note: This signal is not used in RMII mode.  2013-2015 Microchip Technology Inc. DS00001987A-page 7

LAN8740A/LAN8740Ai TABLE 2-1: MII/RMII SIGNALS (CONTINUED) Num Pins Name Symbol Buffer Type Description 1 Receive RXD0 VO8 Bit 0 of the 4 (2 in RMII mode) data bits that are Data 0 sent by the transceiver on the receive path. PHY Operat- MODE0 VIS Combined with MODE1 and MODE2, this configu- ing Mode 0 (PU) ration strap sets the default PHY mode. Configuration Strap See Note1 for more information on configuration straps. Note: Refer to Section 3.7.2, "MODE[2:0]: Mode Configuration" for additional details. 1 Receive RXD1 VO8 Bit 1 of the 4 (2 in RMII mode) data bits that are Data 1 sent by the transceiver on the receive path. PHY Operat- MODE1 VIS Combined with MODE0 and MODE2, this configu- ing Mode 1 (PU) ration strap sets the default PHY mode. Configuration Strap See Note1 for more information on configuration straps. Note: Refer to Section 3.7.2, "MODE[2:0]: Mode Configuration" for additional details. 1 Receive RXD2 VO8 Bit 2 of the 4 (in MII mode) data bits that are sent by Data 2 the transceiver on the receive path. (MII Mode) Note: This signal is not used in RMII mode. Power Man- nPME VO8 When in RMII mode, this pin may be used alterna- agement Event tively as an active low Power Management Event Output (PME) output. Note: The nPME signal can be optionally con- figured to output on the LED1, LED2, or RXD2/nPME/nINTSEL pins. Refer to Section 3.8.4, "Wake on LAN (WoL)" for additional nPME and WoL information. MII/RMII Mode RMIISEL VIS This configuration strap selects the MII or RMII Select Configu- (PD) mode of operation. When strapped low to VSS, MII ration Strap mode is selected. When strapped high to VDDIO RMII mode is selected. See Note1 for more information on configuration straps. Note: Refer to Section 3.7.3, "RMIISEL: MII/RMII Mode Configuration" for addi- tional details. DS00001987A-page 8  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai TABLE 2-1: MII/RMII SIGNALS (CONTINUED) Num Pins Name Symbol Buffer Type Description 1 Receive RXD3 VO8 Bit 3 of the 4 (in MII mode) data bits that are sent by Data 3 the transceiver on the receive path. (MII Mode) Note: This signal is not used in RMII mode. PHY Address 2 PHYAD2 VIS Combined with PHYAD0 and PHYAD1, this config- Configuration (PD) uration strap sets the transceiver’s SMI address. Strap See Note1 for more information on configuration straps. Note: Refer to Section 3.7.1, "PHYAD[2:0]: PHY Address Configuration" for addi- tional information. 1 Receive Error RXER VO8 This signal is asserted to indicate that an error was detected somewhere in the frame presently being transferred from the transceiver. This signal is also used in EEE mode as RXER when RXDV=1, and as LPI when RXDV=0. Note: This signal is optional in RMII mode. Receive RXD4 VO8 In Symbol Interface (5B decoding) mode, this sig- Data 4 nal is the MII Receive Data 4 signal, the MSB of the (MII Mode) received 5-bit symbol code-group. Note: Unless configured to the Symbol Inter- face mode, this pin functions as RXER. PHY Address 0 PHYAD0 VIS Combined with PHYAD1 and PHYAD2, this config- Configuration (PD) uration strap sets the transceiver’s SMI address. Strap See Note1 for more information on configuration straps. Note: Refer to Section 3.7.1, "PHYAD[2:0]: PHY Address Configuration" for addi- tional information. 1 Receive Clock RXCLK VO8 In MII mode, this pin is the receive clock output. (MII Mode) • MII (100BASE-TX): 25 MHz • MII (10BASE-T): 2.5 MHz PHY Address 1 PHYAD1 VIS Combined with PHYAD0 and PHYAD2, this config- Configuration (PD) uration strap sets the transceiver’s SMI address. Strap See Note1 for more information on configuration straps. Note: Refer to Section 3.7.1, "PHYAD[2:0]: PHY Address Configuration" for addi- tional information. 1 Receive Data RXDV VO8 Indicates that recovered and decoded data is avail- Valid able on the RXD pins.  2013-2015 Microchip Technology Inc. DS00001987A-page 9

LAN8740A/LAN8740Ai TABLE 2-1: MII/RMII SIGNALS (CONTINUED) Num Pins Name Symbol Buffer Type Description 1 Collision Detect COL VO8 This signal is asserted to indicate detection of a (MII Mode) collision condition in MII mode. Carrier Sense / CRS_DV VO8 This signal is asserted to indicate the receive Receive Data medium is non-idle in RMII mode. When a Valid 10BASE-T packet is received, CRS_DV is (RMII Mode) asserted, but RXD[1:0] is held low until the SFD byte (10101011) is received. Note: Per the RMII standard, transmitted data is not looped back onto the receive data pins in 10BASE-T half-duplex mode. PHY Operat- MODE2 VIS Combined with MODE0 and MODE1, this configu- ing Mode 2 (PU) ration strap sets the default PHY mode. Configuration Strap See Note1 for more information on configuration straps. Note: Refer to Section 3.7.2, "MODE[2:0]: Mode Configuration" for additional details. 1 Carrier Sense CRS VO8 This signal indicates detection of a carrier in MII (MII Mode) (PD) mode. Note1: Configuration strap values are latched on power-on reset and system reset. Configuration straps are iden- tified by an underlined symbol name. Signals that function as configuration straps must be augmented with an external resistor when connected to a load. Refer to Section 3.7, "Configuration Straps" for additional information. DS00001987A-page 10  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai TABLE 2-2: LED PINS Num Pins Name Symbol Buffer Type Description 1 LED 1 LED1 O12 This pin can be used to indicate link activity, link speed, nINT, or nPME as configured via the LED1 Function Select field of the Wakeup Control and Status Register (WUCSR). Note: Refer to Section 3.8.1, "LEDs" and Sec- tion 3.8.4, "Wake on LAN (WoL)" for additional LED information. Interrupt Out- nINT O12 Active low interrupt output. put Note: By default, the nINT signal is output on the nINT/TXER/TXD4 pin. The nINT signal can be optionally configured to output on the LED1 or LED2 pins. Refer to Section 3.6, "Interrupt Management" for additional details on device inter- rupts. Power Man- nPME O12 Active low Power Management Event (PME) out- agement Event put. Output Note: The nPME signal can be optionally con- figured to output on the LED1, LED2, or RXD2/nPME/nINTSEL pins. Refer to Section 3.8.4, "Wake on LAN (WoL)" for additional nPME and WoL information. Regulator Off REGOFF IS This configuration strap is used to disable the inter- Configuration (PD) nal 1.2 V regulator. When the regulator is disabled, Strap external 1.2 V must be supplied to VDDCR. • When REGOFF is pulled high to VDD2A with an external resistor, the internal regulator is disabled. • When REGOFF is floating or pulled low, the internal regulator is enabled (default). See Note1 for more information on configuration straps. Note: Refer to Section 3.7.4, "REGOFF: Inter- nal +1.2 V Regulator Configuration" for additional details.  2013-2015 Microchip Technology Inc. DS00001987A-page 11

LAN8740A/LAN8740Ai TABLE 2-2: LED PINS (CONTINUED) Num Pins Name Symbol Buffer Type Description 1 LED 2 LED2 O12 This pin can be used to indicate link activity, link speed, nINT, or nPME as configured via the LED2 Function Select field of the Wakeup Control and Status Register (WUCSR). Note: Refer to Section 3.8.1, "LEDs" and Sec- tion 3.8.4, "Wake on LAN (WoL)" for additional LED information. Interrupt Out- nINT O12 Active low interrupt output. put Note: By default, the nINT signal is output on the nINT/TXER/TXD4 pin. The nINT signal can be optionally configured to output on the LED1 or LED2 pins. Refer to Section 3.6, "Interrupt Management" for additional details on device inter- rupts. Power Man- nPME O12 Active low Power Management Event (PME) out- agement Event put. Output Note: The nPME signal can be optionally con- figured to output on the LED1, LED2, or RXD2/nPME/nINTSEL pins. Refer to Section 3.8.4, "Wake on LAN (WoL)" for additional nPME and WoL information. nINT/TXER/ nINTSEL IS This configuration strap selects the mode of the TXD4 Function (PU) nINT/TXER/TXD4 pin. Select Configu- ration Strap • When nINTSEL is floated or pulled to VDD2A, nINT is selected for operation on the nINT/TXER/TXD4 pin (default). • When nINTSEL is pulled low to VSS, TXER/TXD4 is selected for operation on the nINT/TXER/TXD4 pin. See Note1 for more information on configuration straps. Note: Refer to See Section 3.8.1.6, "nINTSEL and LED2 Polarity Selection" for addi- tional information. Note1: Configuration strap values are latched on power-on reset and system reset. Configuration straps are iden- tified by an underlined symbol name. Signals that function as configuration straps must be augmented with an external resistor when connected to a load. Refer to Section 3.7, "Configuration Straps" for additional information. DS00001987A-page 12  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai TABLE 2-3: SERIAL MANAGEMENT INTERFACE (SMI) PINS Num Pins Name Symbol Buffer Type Description 1 SMI Data MDIO VIS/ Serial Management Interface data input/output Input/Output VO8 (PU) 1 SMI Clock MDC VIS Serial Management Interface clock TABLE 2-4: ETHERNET PINS Num Pins Name Symbol Buffer Type Description 1 Ethernet TXP AIO Transmit/Receive Positive Channel 1 TX/RX Posi- tive Channel 1 1 Ethernet TXN AIO Transmit/Receive Negative Channel 1 TX/RX Nega- tive Channel 1 1 Ethernet RXP AIO Transmit/Receive Positive Channel 2 TX/RX Posi- tive Channel 2 1 Ethernet RXN AIO Transmit/Receive Negative Channel 2 TX/RX Nega- tive Channel 2 TABLE 2-5: MISCELLANEOUS PINS Num Pins Name Symbol Buffer Type Description 1 External XTAL1 ICLK External crystal input Crystal Input External CLKIN ICLK Single-ended clock oscillator input. Clock Input Note: When using a single ended clock oscillator, XTAL2 should be left uncon- nected. 1 External XTAL2 OCLK External crystal output Crystal Out- put 1 External nRST VIS System reset. This signal is active low. Reset (PU)  2013-2015 Microchip Technology Inc. DS00001987A-page 13

LAN8740A/LAN8740Ai TABLE 2-6: ANALOG REFERENCE PINS Num Pins Name Symbol Buffer Type Description 1 External 1% RBIAS AI This pin requires connection of a 12.1 kΩ (1%) Bias Resistor resistor to ground. Input Refer to the LAN8740A/LAN8740Ai reference schematic for connection information. Note: The nominal voltage is 1.2 V and the resistor will dissipate approximately 1mW of power. TABLE 2-7: POWER PINS Num Pins Name Symbol Buffer Type Description 1 +1.8 V to +3.3V VDDIO P +1.8 V to +3.3 V variable I/O power. Variable I/O Power Refer to the LAN8740A/LAN8740Ai reference schematic for connection information. 1 +1.2 V Digital VDDCR P Supplied by the on-chip regulator unless config- Core Power ured for regulator off mode via the REGOFF con- Supply figuration strap. Refer to the LAN8740A/LAN8740Ai reference schematic for connection information. Note: 1 µF and 470 pF decoupling capaci- tors in parallel to ground should be used on this pin. 1 +3.3 V Channel VDD1A P +3.3 V Analog Port Power to Channel 1. 1 Analog Port Power Refer to the LAN8740A/LAN8740Ai reference schematic for connection information. 1 +3.3 V Channel VDD2A P +3.3 V Analog Port Power to Channel 2 and the 2 Analog Port internal regulator. Power Refer to the LAN8740A/LAN8740Ai reference schematic for connection information. 1 Ground VSS P Common ground. This exposed pad must be con- nected to the ground plane with a via array. DS00001987A-page 14  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 2.1 Pin Assignments TABLE 2-8: 32-VQFN PACKAGE PIN ASSIGNMENTS Pin Num Pin Name Pin Num Pin Name 1 VDD2A 17 MDC 2 LED2/nINT/nPME/nINTSEL 18 nINT/TXER/TXD4 3 LED1/nINT/nPME/REGOFF 19 nRST 4 XTAL2 20 TXCLK 5 XTAL1/CLKIN 21 TXEN 6 VDDCR 22 TXD0 7 RXCLK/PHYAD1 23 TXD1 8 RXD3/PHYAD2 24 TXD2 9 RXD2/nPME/RMIISEL 25 TXD3 10 RXD1/MODE1 26 RXDV 11 RXD0/MODE0 27 VDD1A 12 VDDIO 28 TXN 13 RXER/RXD4/PHYAD0 29 TXP 14 CRS 30 RXN 15 COL/CRS_DV/MODE2 31 RXP 16 MDIO 32 RBIAS  2013-2015 Microchip Technology Inc. DS00001987A-page 15

LAN8740A/LAN8740Ai 2.2 Buffer Types TABLE 2-9: BUFFER TYPES Buffer Type Description IS Schmitt-triggered input O12 Output with 12 mA sink and 12 mA source VIS Variable voltage Schmitt-triggered input VO8 Variable voltage output with 8 mA sink and 8 mA source VOD8 Variable voltage open-drain output with 8 mA sink PU 50 µA (typical) internal pull-up. Unless otherwise noted in the pin description, internal pull-ups are always enabled. Note: Internal pull-up resistors prevent unconnected inputs from floating. Do not rely on internal resistors to drive signals external to the device. When connected to a load that must be pulled high, an external resistor must be added. PD 50 µA (typical) internal pull-down. Unless otherwise noted in the pin description, internal pull- downs are always enabled. Note: Internal pull-down resistors prevent unconnected inputs from floating. Do not rely on internal resistors to drive signals external to the device. When connected to a load that must be pulled low, an external resistor must be added. AI Analog input AIO Analog bi-directional ICLK Crystal oscillator input pin OCLK Crystal oscillator output pin P Power pin Note: The digital signals are not 5 V tolerant. Refer to Section 5.1, "Absolute Maximum Ratings*" for additional buffer information. Note: Sink and source capabilities are dependent on the VDDIO voltage. Refer to Section 5.1, "Absolute Maxi- mum Ratings*" for additional information. DS00001987A-page 16  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 3.0 FUNCTIONAL DESCRIPTION This chapter provides functional descriptions of the various device features. These features have been categorized into the following sections: • Transceiver • Auto-Negotiation • HP Auto-MDIX Support • MAC Interface • Serial Management Interface (SMI) • Interrupt Management • Configuration Straps • Miscellaneous Functions • Application Diagrams 3.1 Transceiver 3.1.1 100BASE-TX TRANSMIT The 100BASE-TX transmit data path is shown in Figure 3-1. Each major block is explained in the following subsections. FIGURE 3-1: 100BASE-TX TRANSMIT DATA PATH TX_CLK (for MII only) PLL MAC Ext Ref_CLK (for RMII only) MII 25 MHz by 4 bits 25 MHz 4B/5B 25 MHz by Scrambler or MII/RMII by 4 bits Encoder 5 bits and PISO RMII 50 MHz by 2 bits NRZI MLT-3 Tx 125 Mbps Serial NRZI MLT-3 Converter Converter Driver MLT-3 Magnetics MLT-3 RJ45 MLT-3 CAT-5 3.1.1.1 100BASE-TX Transmit Data Across the MII/RMII Interface For MII, the MAC controller drives the transmit data onto the TXD bus and asserts TXEN to indicate valid data. The data is latched by the transceiver’s MII block on the rising edge of TXCLK. The data is in the form of 4-bit wide 25 MHz data. For RMII, the MAC controller drives the transmit data onto the TXD bus and asserts TXEN to indicate valid data. The data is latched by the transceiver’s RMII block on the rising edge of REF_CLK. The data is in the form of 2-bit wide 50 MHz data. 3.1.1.2 4B/5B Encoding The transmit data passes from the MII/RMII block to the 4B/5B encoder. This block encodes the data from 4-bit nibbles to 5-bit symbols (known as “code-groups”) according to Table 3-1. Each 4-bit data-nibble is mapped to 16 of the 32 pos- sible code-groups. The remaining 16 code-groups are either used for control information or are not valid. The first 16 code-groups are referred to by the hexadecimal values of their corresponding data nibbles, 0 through F. The remaining code-groups are given letter designations with slashes on either side. For example, an IDLE code-group is /I/, a transmit error code-group is /H/, etc.  2013-2015 Microchip Technology Inc. DS00001987A-page 17

LAN8740A/LAN8740Ai TABLE 3-1: 4B/5B CODE TABLE Code Group Sym Receiver Interpretation Transmitter Interpretation 11110 0 0 0000 DATA 0 0000 DATA 01001 1 1 0001 1 0001 10100 2 2 0010 2 0010 10101 3 3 0011 3 0011 01010 4 4 0100 4 0100 01011 5 5 0101 5 0101 01110 6 6 0110 6 0110 01111 7 7 0111 7 0111 10010 8 8 1000 8 1000 10011 9 9 1001 9 1001 10110 A A 1010 A 1010 10111 B B 1011 B 1011 11010 C C 1100 C 1100 11011 D D 1101 D 1101 11100 E E 1110 E 1110 11101 F F 1111 F 1111 11111 I IDLE Sent after /T/R until TXEN 11000 J First nibble of SSD, translated to “0101” Sent for rising TXEN following IDLE, else RXER 10001 K Second nibble of SSD, translated to Sent for rising TXEN “0101” following J, else RXER 01101 T First nibble of ESD, causes de-assertion of Sent for falling TXEN CRS if followed by /R/, else assertion of RXER 00111 R Second nibble of ESD, causes deasser- Sent for falling TXEN tion of CRS if following /T/, else assertion of RXER 00100 H Transmit Error Symbol Sent for rising TXER 00110 V INVALID, RXER if during RXDV INVALID 11001 V INVALID, RXER if during RXDV INVALID 00000 V Indicates to receiver that the transmitter Sent due to LPI. Used to tell receiver will be going to LPI before transmitter goes to LPI. Also used for refresh cycles during LPI. 00001 V INVALID, RXER if during RXDV INVALID 00010 V INVALID, RXER if during RXDV INVALID 00011 V INVALID, RXER if during RXDV INVALID 00101 V INVALID, RXER if during RXDV INVALID 01000 V INVALID, RXER if during RXDV INVALID 01100 V INVALID, RXER if during RXDV INVALID 10000 V INVALID, RXER if during RXDV INVALID DS00001987A-page 18  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 3.1.1.3 Scrambling Repeated data patterns (especially the IDLE code-group) can have power spectral densities with large narrow-band peaks. Scrambling the data helps eliminate these peaks and spread the signal power more uniformly over the entire channel bandwidth. This uniform spectral density is required by FCC regulations to prevent excessive EMI from being radiated by the physical wiring. The seed for the scrambler is generated from the transceiver address, PHYAD, ensuring that in multiple-transceiver applications, such as repeaters or switches, each transceiver will have its own scrambler sequence. The scrambler also performs the Parallel In Serial Out conversion (PISO) of the data. 3.1.1.4 NRZI and MLT-3 Encoding The scrambler block passes the 5-bit wide parallel data to the NRZI converter where it becomes a serial 125 MHz NRZI data stream. The NRZI is encoded to MLT-3. MLT-3 is a tri-level code where a change in the logic level represents a code bit “1” and the logic output remaining at the same level represents a code bit “0”. 3.1.1.5 100M Transmit Driver The MLT3 data is then passed to the analog transmitter, which drives the differential MLT-3 signal, on outputs TXP and TXN, to the twisted pair media across a 1:1 ratio isolation transformer. The 10BASE-T and 100BASE-TX signals pass through the same transformer so that common “magnetics” can be used for both. The transmitter drives into the 100 Ω impedance of the CAT-5 cable. Cable termination and impedance matching require external components. 3.1.1.6 100M Phase Lock Loop (PLL) The 100M PLL locks onto reference clock and generates the 125 MHz clock used to drive the 125MHz logic and the 100BASE-TX transmitter. 3.1.2 100BASE-TX RECEIVE The 100BASE-TX receive data path is shown in Figure 3-2. Each major block is explained in the following subsections. FIGURE 3-2: 100BASE-TX RECEIVE DATA PATH RX_CLK (for MII only) PLL MAC Ext Ref_CLK (for RMII only) 25 MHz 25 MHz by MII 25 MHz by 4 bits by 4 bits 4B/5B 5 bits Descrambler or MII/RMII RMII 50 MHz by 2 bits Decoder and SIPO 125 Mbps Serial DSP: Timing NRZI NRZI MLT-3 MLT-3 recovery, Equalizer Converter Converter and BLW Correction A/D MLT-3 MLT-3 MLT-3 Magnetics RJ45 CAT-5 Converter 6 bit Data  2013-2015 Microchip Technology Inc. DS00001987A-page 19

LAN8740A/LAN8740Ai 3.1.2.1 100M Receive Input The MLT-3 from the cable is fed into the transceiver (on inputs RXP and RXN) via a 1:1 ratio transformer. The ADC samples the incoming differential signal at a rate of 125M samples per second. Using a 64-level quanitizer, it generates 6 digital bits to represent each sample. The DSP adjusts the gain of the ADC according to the observed signal levels such that the full dynamic range of the ADC can be used. 3.1.2.2 Equalizer, Baseline Wander Correction and Clock and Data Recovery The 6 bits from the ADC are fed into the DSP block. The equalizer in the DSP section compensates for phase and ampli- tude distortion caused by the physical channel consisting of magnetics, connectors, and CAT- 5 cable. The equalizer can restore the signal for any good-quality CAT-5 cable between 1m and 100 m. If the DC content of the signal is such that the low-frequency components fall below the low frequency pole of the iso- lation transformer, then the droop characteristics of the transformer will become significant and Baseline Wander (BLW) on the received signal will result. To prevent corruption of the received data, the transceiver corrects for BLW and can receive the ANSI X3.263-1995 FDDI TP-PMD defined “killer packet” with no bit errors. The 100M PLL generates multiple phases of the 125 MHz clock. A multiplexer, controlled by the timing unit of the DSP, selects the optimum phase for sampling the data. This is used as the received recovered clock. This clock is used to extract the serial data from the received signal. 3.1.2.3 NRZI and MLT-3 Decoding The DSP generates the MLT-3 recovered levels that are fed to the MLT-3 converter. The MLT-3 is then converted to an NRZI data stream. 3.1.2.4 Descrambling The descrambler performs an inverse function to the scrambler in the transmitter and also performs the Serial In Parallel Out (SIPO) conversion of the data. During reception of IDLE (/I/) symbols. the descrambler synchronizes its descrambler key to the incoming stream. Once synchronization is achieved, the descrambler locks on this key and is able to descramble incoming data. Special logic in the descrambler ensures synchronization with the remote transceiver by searching for IDLE symbols within a window of 4000 bytes (40 µs). This window ensures that a maximum packet size of 1514 bytes, allowed by the IEEE 802.3 standard, can be received with no interference. If no IDLE-symbols are detected within this time-period, receive operation is aborted and the descrambler re-starts the synchronization process. 3.1.2.5 Alignment The de-scrambled signal is then aligned into 5-bit code-groups by recognizing the /J/K/ Start-of-Stream Delimiter (SSD) pair at the start of a packet. Once the code-word alignment is determined, it is stored and utilized until the next start of frame. 3.1.2.6 5B/4B Decoding The 5-bit code-groups are translated into 4-bit data nibbles according to the 4B/5B table. The translated data is pre- sented on the RXD[3:0] signal lines. The SSD, /J/K/, is translated to “0101 0101” as the first 2 nibbles of the MAC pre- amble. Reception of the SSD causes the transceiver to assert the receive data valid signal, indicating that valid data is available on the RXD bus. Successive valid code-groups are translated to data nibbles. Reception of either the End of Stream Delimiter (ESD) consisting of the /T/R/ symbols, or at least two /I/ symbols causes the transceiver to de-assert the carrier sense and receive data valid signals. Note: These symbols are not translated into data. DS00001987A-page 20  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 3.1.2.7 Receive Data Valid Signal The Receive Data Valid signal (RXDV) indicates that recovered and decoded nibbles are being presented on the RXD[3:0] outputs synchronous to RXCLK. RXDV becomes active after the /J/K/ delimiter has been recognized and RXD is aligned to nibble boundaries. It remains active until either the /T/R/ delimiter is recognized or link test indicates failure or SIGDET becomes false. RXDV is asserted when the first nibble of translated /J/K/ is ready for transfer over the Media Independent Interface (MII mode). FIGURE 3-3: RELATIONSHIP BETWEEN RECEIVED DATA AND SPECIFIC MII SIGNALS CLEAR-TEXT J K 5 5 5 D data data data data T R Idle RX_CLK RX_DV RXD 5 5 5 5 5 D data data data data 3.1.2.8 Receiver Errors During a frame, unexpected code-groups are considered receive errors. Expected code groups are the DATA set (0 through F), and the /T/R/ (ESD) symbol pair. When a receive error occurs, the RXER signal is asserted and arbitrary data is driven onto the RXD[3:0] lines. Should an error be detected during the time that the /J/K/ delimiter is being decoded (bad SSD error), RXER is asserted true and the value ‘1110’ is driven onto the RXD[3:0] lines. Note that the Valid Data signal is not yet asserted when the bad SSD error occurs. 3.1.2.9 100M Receive Data Across the MII/RMII Interface In MII mode, the 4-bit data nibbles are sent to the MII block. These data nibbles are clocked to the controller at a rate of 25 MHz. The controller samples the data on the rising edge of RXCLK. To ensure that the setup and hold require- ments are met, the nibbles are clocked out of the transceiver on the falling edge of RXCLK. RXCLK is the 25 MHz output clock for the MII bus. It is recovered from the received data to clock the RXD bus. If there is no received signal, it is derived from the system reference clock (XTAL1/CLKIN). When tracking the received data, RXCLK has a maximum jitter of 0.8 ns (provided that the jitter of the input clock, XTAL1/CLKIN, is below 100 ps). In RMII mode, the 2-bit data nibbles are sent to the RMII block. These data nibbles are clocked to the controller at a rate of 50 MHz. The controller samples the data on the rising edge of XTAL1/CLKIN (REF_CLK). To ensure that the setup and hold requirements are met, the nibbles are clocked out of the transceiver on the falling edge of XTAL1/CLKIN (REF_CLK). 3.1.3 10BASE-T TRANSMIT Data to be transmitted comes from the MAC layer controller. The 10BASE-T transmitter receives 4-bit nibbles from the MII at a rate of 2.5 MHz and converts them to a 10 Mbps serial data stream. The data stream is then Manchester- encoded and sent to the analog transmitter, which drives a signal onto the twisted pair via the external magnetics. The 10M transmitter uses the following blocks: • MII (digital) • TX 10M (digital) • 10M Transmitter (analog) • 10M PLL (analog)  2013-2015 Microchip Technology Inc. DS00001987A-page 21

LAN8740A/LAN8740Ai 3.1.3.1 10M Transmit Data Across the MII/RMII Interface The MAC controller drives the transmit data onto the TXD bus. For MII, when the controller has driven TXEN high to indicate valid data, the data is latched by the MII block on the rising edge of TXCLK. The data is in the form of 4-bit wide 2.5 MHz data. For RMII, TXD[1:0] shall transition synchronously with respect to REF_CLK. When TXEN is asserted, TXD[1:0] are accepted for transmission by the device. TXD[1:0] shall be “00” to indicate idle when TXEN is deasserted. Values of TXD[1:0] other than “00” when TXEN is deasserted are reserved for out-of-band signaling (to be defined). Values other than “00” on TXD[1:0] while TXEN is deasserted shall be ignored by the device.TXD[1:0] shall provide valid data for each REF_CLK period while TXEN is asserted. In order to comply with legacy 10BASE-T MAC/Controllers, in half-duplex mode the transceiver loops back the trans- mitted data, on the receive path. This does not confuse the MAC/Controller since the COL signal is not asserted during this time. The transceiver also supports the SQE (Heartbeat) signal. See Section 3.8.9, "Collision Detect", for more details. 3.1.3.2 Manchester Encoding The 4-bit wide data is sent to the 10M TX block. The nibbles are converted to a 10 Mbps serial NRZI data stream. The 10M PLL locks onto the external clock or internal oscillator and produces a 20 MHz clock. This is used to Manchester encode the NRZ data stream. When no data is being transmitted (TXEN is low), the 10M TX block outputs Normal Link Pulses (NLPs) to maintain communications with the remote link partner. 3.1.3.3 10M Transmit Drivers The Manchester-encoded data is sent to the analog transmitter where it is shaped and filtered before being driven out as a differential signal across the TXP and TXN outputs. 3.1.4 10BASE-T RECEIVE The 10BASE-T receiver gets the Manchester- encoded analog signal from the cable via the magnetics. It recovers the receive clock from the signal and uses this clock to recover the NRZI data stream. This 10M serial data is converted to 4-bit data nibbles which are passed to the controller via MII at a rate of 2.5 MHz. This 10M receiver uses the following blocks: • Filter and SQUELCH (analog) • 10M PLL (analog) • RX 10M (digital) • MII (digital) 3.1.4.1 10M Receive Input and Squelch The Manchester signal from the cable is fed into the transceiver (on inputs RXP and RXN) via 1:1 ratio magnetics. It is first filtered to reduce any out-of-band noise. It then passes through a SQUELCH circuit. The SQUELCH is a set of amplitude and timing comparators that normally reject differential voltage levels below 300 mV and detect and recognize differential voltages above 585 mV. 3.1.4.2 Manchester Decoding The output of the SQUELCH goes to the 10M RX block where it is validated as Manchester encoded data. The polarity of the signal is also checked. If the polarity is reversed (local RXP is connected to RXN of the remote partner and vice versa), the condition is identified and corrected. The reversed condition is indicated by the XPOL bit of the Special Con- trol/Status Indications Register. The 10M PLL is locked onto the received Manchester signal, from which the 20MHz cock is generated. Using this clock, the Manchester encoded data is extracted and converted to a 10 MHz NRZI data stream. It is then converted from serial to 4-bit wide parallel data. The 10M RX block also detects valid 10BASE-T IDLE signals - Normal Link Pulses (NLPs) - to maintain the link. DS00001987A-page 22  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 3.1.4.3 10M Receive Data Across the MII/RMII Interface For MII, the 4-bit data nibbles are sent to the MII block. In MII mode, these data nibbles are valid on the rising edge of the 2.5 MHz RXCLK. For RMII, the 2-bit data nibbles are sent to the RMII block. In RMII mode, these data nibbles are valid on the rising edge of the RMII REF_CLK. Note: RXDV goes high with the SFD. 3.1.4.4 Jabber Detection Jabber is a condition in which a station transmits for a period of time longer than the maximum permissible packet length, usually due to a fault condition, which results in holding the TXEN input for a long period. Special logic is used to detect the jabber state and abort the transmission to the line within 45 ms. Once TXEN is deasserted, the logic resets the jabber condition. As shown in Section 4.2.2, "Basic Status Register", the Jabber Detect bit indicates that a jabber condition was detected. 3.2 Auto-Negotiation The purpose of the auto-negotiation function is to automatically configure the transceiver to the optimum link parameters based on the capabilities of its link partner. Auto-negotiation is a mechanism for exchanging configuration information between two link-partners and automatically selecting the highest performance mode of operation supported by both sides. Auto-negotiation is fully defined in clause 28 of the IEEE 802.3 specification. Once auto-negotiation has completed, information about the resolved link can be passed back to the controller via the Serial Management Interface (SMI). The results of the negotiation process are reflected in the Speed Indication bits of the PHY Special Control/Status Register, as well as in the Auto Negotiation Link Partner Ability Register. The auto-nego- tiation protocol is a purely physical layer activity and proceeds independently of the MAC controller. The advertised capabilities of the transceiver are stored in the Auto Negotiation Advertisement Register. The default advertised by the transceiver is determined by user-defined on-chip signal options. The following blocks are activated during an auto-negotiation session: • Auto-negotiation (digital) • 100M ADC (analog) • 100M PLL (analog) • 100M equalizer/BLW/clock recovery (DSP) • 10M SQUELCH (analog) • 10M PLL (analog) • 10M Transmitter (analog) When enabled, auto-negotiation is started by the occurrence of one of the following events: • Hardware reset • Software reset • Power-down reset • Link status down • Setting the Restart Auto-Negotiate bit of the Basic Control Register On detection of one of these events, the transceiver begins auto-negotiation by transmitting bursts of Fast Link Pulses (FLP), which are bursts of link pulses from the 10M transmitter. They are shaped as Normal Link Pulses and can pass uncorrupted down CAT-3 or CAT-5 cable. A Fast Link Pulse Burst consists of up to 33 pulses. The 17 odd-numbered pulses, which are always present, frame the FLP burst. The 16 even-numbered pulses, which may be present or absent, contain the data word being transmitted. Presence of a data pulse represents a “1”, while absence represents a “0”. The data transmitted by an FLP burst is known as a “Link Code Word.” These are defined fully in IEEE 802.3 clause 28. In summary, the transceiver advertises 802.3 compliance in its selector field (the first 5 bits of the Link Code Word). It advertises its technology ability according to the bits set in the Auto Negotiation Advertisement Register.  2013-2015 Microchip Technology Inc. DS00001987A-page 23

LAN8740A/LAN8740Ai There are 4 possible matches of the technology abilities. In the order of priority these are: • 100M Full Duplex (Highest Priority) • 100M Half Duplex • 10M Full Duplex • 10M Half Duplex (Lowest Priority) If the full capabilities of the transceiver are advertised (100M, Full Duplex), and if the link partner is capable of 10M and 100M, then auto-negotiation selects 100M as the highest performance mode. If the link partner is capable of half and full duplex modes, then auto-negotiation selects full duplex as the highest performance operation. Once a capability match has been determined, the link code words are repeated with the acknowledge bit set. Any dif- ference in the main content of the link code words at this time will cause auto-negotiation to re-start. Auto-negotiation will also re-start if not all of the required FLP bursts are received. The capabilities advertised during auto-negotiation by the transceiver are initially determined by the logic levels latched on the MODE[2:0] configuration straps after reset completes. These configuration straps can also be used to disable auto-negotiation on power-up. Refer to Section 3.7.2, "MODE[2:0]: Mode Configuration" for additional information. Writing the bits 8 through 5 of the Auto Negotiation Advertisement Register allows software control of the capabilities advertised by the transceiver. Writing the Auto Negotiation Advertisement Register does not automatically re-start auto- negotiation. The Restart Auto-Negotiate bit of the Basic Control Register must be set before the new abilities will be advertised. Auto-negotiation can also be disabled via software by clearing the Auto-Negotiation Enable bit of the Basic Control Register. 3.2.1 PARALLEL DETECTION If the LAN8740A/LAN8740Ai is connected to a device lacking the ability to auto-negotiate (i.e., no FLPs are detected), it is able to determine the speed of the link based on either 100M MLT-3 symbols or 10M Normal Link Pulses. In this case the link is presumed to be half duplex per the IEEE standard. This ability is known as “Parallel Detection.” This feature ensures interoperability with legacy link partners. If a link is formed via parallel detection, then the Link Partner Auto-Negotiation Able bit of the Auto Negotiation Expansion Register is cleared to indicate that the Link Partner is not capable of auto-negotiation. The controller has access to this information via the management interface. If a fault occurs during parallel detection, the Parallel Detection Fault bit of Link Partner Auto-Negotiation Able is set. Auto Negotiation Link Partner Ability Register is used to store the link partner ability information, which is coded in the received FLPs. If the link partner is not auto-negotiation capable, then the Auto Negotiation Link Partner Ability Register is updated after completion of parallel detection to reflect the speed capability of the link partner. 3.2.2 RESTARTING AUTO-NEGOTIATION Auto-negotiation can be restarted at any time by setting the Restart Auto-Negotiate bit of the Basic Control Register. Auto-negotiation will also restart if the link is broken at any time. A broken link is caused by signal loss. This may occur because of a cable break, or because of an interruption in the signal transmitted by the link partner. Auto-negotiation resumes in an attempt to determine the new link configuration. If the management entity re-starts auto-negotiation by setting the Restart Auto-Negotiate bit of the Basic Control Reg- ister, the LAN8740A/LAN8740Ai will respond by stopping all transmission/receiving operations. Once the break_link_- timer is completed in the auto-negotiation state-machine (approximately 1250 ms), auto-negotiation will re-start. In this case, the link partner will have also dropped the link due to lack of a received signal, so it too will resume auto-negoti- ation. 3.2.3 DISABLING AUTO-NEGOTIATION Auto-negotiation can be disabled by setting the Auto-Negotiation Enable bit of the Basic Control Register to zero. The device will then force its speed of operation to reflect the information in the Basic Control Register (Speed Select bit and Duplex Mode bit). These bits should be ignored when auto-negotiation is enabled. 3.2.4 HALF VS. FULL DUPLEX Half duplex operation relies on the CSMA/CD (Carrier Sense Multiple Access / Collision Detect) protocol to handle net- work traffic and collisions. In this mode, the carrier sense signal, CRS, responds to both transmit and receive activity. If data is received while the transceiver is transmitting, a collision results. In full duplex mode, the transceiver is able to transmit and receive data simultaneously. In this mode, CRS responds only to receive activity. The CSMA/CD protocol does not apply and collision detection is disabled. DS00001987A-page 24  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 3.3 HP Auto-MDIX Support HP Auto-MDIX facilitates the use of CAT-3 (10BASE-T) or CAT-5 (100BASE-TX) media UTP interconnect cable without consideration of interface wiring scheme. If a user plugs in either a direct connect LAN cable, or a cross-over patch cable, as shown in Figure 3-4, the device’s Auto-MDIX transceiver is capable of configuring the TXP/TXN and RXP/RXN pins for correct transceiver operation. The internal logic of the device detects the TX and RX pins of the connecting device. Since the RX and TX line pairs are interchangeable, special PCB design considerations are needed to accommodate the symmetrical magnetics and termination of an Auto-MDIX design. The Auto-MDIX function can be disabled via the AMDIXCTRL bit in the Special Control/Status Indications Register. Note: When operating in 10BASE-T or 100BASE-TX manual modes, the Auto-MDIX crossover time can be extended via the Extend Manual 10/100 Auto-MDIX Crossover Time bit of the EDPD NLP/Crossover Time/EEE Configuration Register. Refer to Section 4.2.12, "EDPD NLP/Crossover Time/EEE Configura- tion Register" for additional information. FIGURE 3-4: DIRECT CABLE CONNECTION VS. CROSS-OVER CABLE CONNECTION RJ-45 8-pin straight-through RJ-45 8-pin cross-over for for 10BASE-T/100BASE-TX 10BASE-T/100BASE-TX signaling signaling TXP 1 1 TXP TXP 1 1 TXP TXN 2 2 TXN TXN 2 2 TXN RXP 3 3 RXP RXP 3 3 RXP Not Used 4 4 Not Used Not Used 4 4 Not Used Not Used 5 5 Not Used Not Used 5 5 Not Used RXN 6 6 RXN RXN 6 6 RXN Not Used 7 7 Not Used Not Used 7 7 Not Used Not Used 8 8 Not Used Not Used 8 8 Not Used Direct Connect Cable Cross-Over Cable  2013-2015 Microchip Technology Inc. DS00001987A-page 25

LAN8740A/LAN8740Ai 3.4 MAC Interface The MII/RMII block is responsible for communication with the MAC controller. Special sets of hand-shake signals are used to indicate that valid received/transmitted data is present on the 4 bit receive/transmit bus. The device must be configured in MII or RMII mode. This is done by specific pin strapping configurations. Refer to Sec- tion 3.4.3, "MII vs. RMII Configuration" for information on pin strapping and how the pins are mapped differently. 3.4.1 MII The MII includes 16 interface signals: • Transmit data - TXD[3:0] • Transmit strobe - TXEN • Transmit clock - TXCLK • Transmit error - TXER/TXD4 • Receive data - RXD[3:0] • Receive strobe - RXDV • Receive clock - RXCLK • Receive error - RXER/RXD4/PHYAD0 • Collision indication - COL • Carrier sense - CRS In MII mode, on the transmit path, the transceiver drives the transmit clock, TXCLK, to the controller. The controller syn- chronizes the transmit data to the rising edge of TXCLK. The controller drives TXEN high to indicate valid transmit data. The controller drives TXER high when a transmit error is detected. On the receive path, the transceiver drives both the receive data, RXD[3:0], and the RXCLK signal. The controller clocks in the receive data on the rising edge of RXCLK when the transceiver drives RXDV high. The transceiver drives RXER high when a receive error is detected. 3.4.2 RMII The device supports the low pin count Reduced Media Independent Interface (RMII) intended for use between Ethernet transceivers and switch ASICs. Under IEEE 802.3, an MII comprised of 16 pins for data and control is defined. In devices incorporating many MACs or transceiver interfaces such as switches, the number of pins can add significant cost as the port counts increase. RMII reduces this pin count while retaining a management interface (MDIO/MDC) that is identical to MII. The RMII interface has the following characteristics: • It is capable of supporting 10 Mbps and 100 Mbps data rates • A single clock reference is used for both transmit and receive • It provides independent 2-bit (di-bit) wide transmit and receive data paths • It uses LVCMOS signal levels, compatible with common digital CMOS ASIC processes The RMII includes the following interface signals (1 optional): • Transmit data - TXD[1:0] • Transmit strobe - TXEN • Receive data - RXD[1:0] • Receive error - RXER (Optional) • Carrier sense - CRS_DV • Reference Clock - (RMII references usually define this signal as REF_CLK) DS00001987A-page 26  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 3.4.2.1 CRS_DV - Carrier Sense/Receive Data Valid The CRS_DV is asserted by the device when the receive medium is non-idle. CRS_DV is asserted asynchronously on detection of carrier due to the criteria relevant to the operating mode. In 10BASE-T mode when squelch is passed, or in 100BASE-TX mode when 2 non-contiguous zeroes in 10 bits are detected, the carrier is said to be detected. Loss of carrier shall result in the deassertion of CRS_DV synchronous to the cycle of REF_CLK which presents the first di-bit of a nibble onto RXD[1:0] (i.e., CRS_DV is deasserted only on nibble boundaries). If the device has additional bits to be presented on RXD[1:0] following the initial deassertion of CRS_DV, then the device shall assert CRS_DV on cycles of REF_CLK which present the second di-bit of each nibble and de-assert CRS_DV on cycles of REF_CLK which pres- ent the first di-bit of a nibble. The result is, starting on nibble boundaries, CRS_DV toggles at 25 MHz in 100 Mbps mode and 2.5 MHz in 10 Mbps mode when CRS ends before RXDV (i.e., the FIFO still has bits to transfer when the carrier event ends). Therefore, the MAC can accurately recover RXDV and CRS. During a false carrier event, CRS_DV shall remain asserted for the duration of carrier activity. The data on RXD[1:0] is considered valid once CRS_DV is asserted. However, since the assertion of CRS_DV is asynchronous relative to REF_CLK, the data on RXD[1:0] shall be “00” until proper receive signal decoding takes place. 3.4.2.2 Reference Clock (REF_CLK) The RMII REF_CLK is a continuous clock that provides the timing reference for CRS_DV, RXD[1:0], TXEN, TXD[1:0] and RXER. The device uses REF_CLK as the network clock such that no buffering is required on the transmit data path. However, on the receive data path, the receiver recovers the clock from the incoming data stream, and the device uses elasticity buffering to accommodate for differences between the recovered clock and the local REF_CLK.  2013-2015 Microchip Technology Inc. DS00001987A-page 27

LAN8740A/LAN8740Ai 3.4.3 MII VS. RMII CONFIGURATION The device must be configured to support the MII or RMII bus for connectivity to the MAC. This configuration is done via the RMIISEL configuration strap. MII or RMII mode selection is configured based on the strapping of the RMIISEL configuration strap as described in Section 3.7.3, "RMIISEL: MII/RMII Mode Configuration". Additionally, the MII/RMII interface can be disabled (outputs driven low) via the Interface Disable bit of the Wakeup Control and Status Register (WUCSR). Most of the MII and RMII pins are multiplexed. Table3-2, "MII/RMII Signal Mapping" describes the relationship of the related device pins to the MII and RMII mode signal names. TABLE 3-2: MII/RMII SIGNAL MAPPING Pin Name MII Mode RMII Mode TXD0 TXD0 TXD0 TXD1 TXD1 TXD1 TXEN TXEN TXEN RXER/ RXER RXER RXD4/PHYAD0 (see Note 1) COL/CRS_DV/MODE2 COL CRS_DV RXD0/MODE0 RXD0 RXD0 RXD1/MODE1 RXD1 RXD1 TXD2 TXD2 (see Note 2) TXD3 TXD3 (see Note 2) nINT/TXER/TXD4 TXER/ TXD4 CRS CRS RXDV RXDV RXD2/RMIISEL RXD2 RXD3/PHYAD2 RXD3 TXCLK TXCLK RXCLK/PHYAD1 RXCLK XTAL1/CLKIN XTAL1/CLKIN REF_CLK Note1: The RXER signal is optional on the RMII bus. This signal is required by the transceiver, but it is optional for the MAC. The MAC can choose to ignore or not use this signal. 2: In RMII mode, this pin needs to be tied to VSS. DS00001987A-page 28  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 3.5 Serial Management Interface (SMI) The Serial Management Interface is used to control the device and obtain its status. This interface supports registers 0 through 6 as required by clause 22 of the 802.3 standard, as well as “vendor-specific” registers 16 to 31 allowed by the specification. Device registers are detailed in Chapter 4, "Register Descriptions". At the system level, SMI provides 2 signals: MDIO and MDC. The MDC signal is an aperiodic clock provided by the Station Management Controller (SMC). MDIO is a bi-directional data SMI input/output signal that receives serial data (commands) from the controller SMC and sends serial data (status) to the SMC. The minimum time between edges of the MDC is 160 ns. There is no maximum time between edges. The minimum cycle time (time between two consecutive rising or two consecutive falling edges) is 400 ns. These modest timing requirements allow this interface to be easily driven by the I/O port of a microcontroller. The data on the MDIO line is latched on the rising edge of the MDC. The frame structure and timing of the data is shown in Figure 3-5 and Figure 3-6. The timing relationships of the MDIO signals are further described in Section 5.6.5, "SMI Timing". FIGURE 3-5: MDIO TIMING AND FRAME STRUCTURE - READ CYCLE Read Cycle MDC ... MDIO 32 1's 0 1 1 0 A4 A3 A2 A1 A0 R4 R3 R2 R1 R0 D15 D14 ... D1 D0 Start of OP Turn Preamble PHY Address Register Address Data Frame Code Around Data To Phy Data From Phy FIGURE 3-6: MDIO TIMING AND FRAME STRUCTURE - WRITE CYCLE Write Cycle MDC ... MDIO 32 1's 0 1 0 1 A4 A3 A2 A1 A0 R4 R3 R2 R1 R0 D15 D14 ... D1 D0 Start of OP Turn Preamble PHY Address Register Address Data Frame Code Around Data To Phy  2013-2015 Microchip Technology Inc. DS00001987A-page 29

LAN8740A/LAN8740Ai 3.6 Interrupt Management The device management interface supports an interrupt capability that is not a part of the IEEE 802.3 specification. This interrupt capability generates an active low asynchronous interrupt signal on the nINT output whenever certain events are detected as setup by the Interrupt Mask Register. The nINT signal can be selected to output on three different pins: • nINT/TXER/TXD4 (See Section 3.7.5, "nINTSEL: nINT/TXER/TXD4 Configuration" for configuration information) • LED1 (See Section 3.8.1, "LEDs" for configuration information) • LED2 (See Section 3.8.1, "LEDs" for configuration information) The device’s interrupt system provides two modes, a Primary interrupt mode and an Alternative interrupt mode. Both systems will assert the nINT pin low when the corresponding mask bit is set. These modes differ only in how they de- assert the nINT interrupt output. These modes are detailed in the following subsections. Note: The Primary interrupt mode is the default interrupt mode after a power-up or hard reset. The Alternative interrupt mode requires setup after a power-up or hard reset. Note: In addition to the main interrupts described in this section, an nPME pin is provided exclusively for WoL specific interrupts. Refer to Section 3.8.4, "Wake on LAN (WoL)" for additional information on nPME. Note: Due to the multiplexing of nINT and TXER on the same pin, when EEE and WoL are both enabled, nINT and/or nPME must be multiplexed on LED1 and/or LED2. Refer to Section 3.8.1, "LEDs" and Section 3.8.4, "Wake on LAN (WoL)" for additional information. DS00001987A-page 30  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 3.6.1 PRIMARY INTERRUPT SYSTEM The Primary interrupt system is the default interrupt mode (ALTINT bit of the Mode Control/Status Register is “0”). The Primary interrupt system is always selected after power-up or hard reset. In this mode, to set an interrupt, set the cor- responding mask bit in the Interrupt Mask Register (see Table 3-3). Then when the event to assert nINT is true, the nINT output will be asserted. When the corresponding event to deassert nINT is true, then the nINT will be de-asserted. TABLE 3-3: INTERRUPT MANAGEMENT TABLE Event to Assert Event to Mask Interrupt Source Flag Interrupt Source nINT De-Assert nINT 30.8 29.8 WoL 3.32784.7:4 nPME Rising 3.32784.7:4 or’ed together 3.32784.7:4 low or reading register 29 or’ed together 30.7 29.7 ENERGYON 17.1 ENERGYON Rising 17.1 (see Falling 17.1 or Note 1) Reading register 29 30.6 29.6 Auto-Negotiation 1.5 Auto-Negotiate Rising 1.5 Falling 1.5 or Complete Complete Reading register 29 30.5 29.5 Remote Fault 1.4 Remote Fault Rising 1.4 Falling 1.4, or Detected Reading register 1 or Reading register 29 30.4 29.4 Link Down 1.2 Link Status Falling 1.2 Reading register 1 or Reading register 29 30.3 29.3 Auto-Negotiation 5.14 Acknowledge Rising 5.14 Falling 5.14 or LP Acknowledge Reading register 29 30.2 29.2 Parallel Detection 6.4 Parallel Detec- Rising 6.4 Falling 6.4 or Fault tion Fault Reading register 6, or Reading register 29, or Re-Auto Negotiate or Link down 30.1 29.1 Auto-Negotiation 6.1 Page Received Rising 6.1 Falling 6.1 or Page Received Reading register 6, or Reading register 29, or Re-Auto Negotiate, or Link down. Note1: If the mask bit is enabled and nINT has been de-asserted while ENERGYON is still high, nINT will assert for 256 ms, approximately one second after ENERGYON goes low when the Cable is unplugged. To prevent an unexpected assertion of nINT, the ENERGYON interrupt mask should always be cleared as part of the ENERGYON interrupt service routine. Note: The ENERGYON bit in the Mode Control/Status Register is defaulted to a ‘1’ at the start of the signal acqui- sition process, therefore the INT7 bit in the Interrupt Mask Register will also read as a ‘1’ at power-up. If no signal is present, then both ENERGYON and INT7 will clear within a few milliseconds.  2013-2015 Microchip Technology Inc. DS00001987A-page 31

LAN8740A/LAN8740Ai 3.6.2 ALTERNATE INTERRUPT SYSTEM The Alternate interrupt system is enabled by setting the ALTINT bit of the Mode Control/Status Register to “1”. In this mode, to set an interrupt, set the corresponding bit of the in the Mask Register 30, (see Table 3-4). To Clear an interrupt, either clear the corresponding bit in the Interrupt Mask Register to deassert the nINT output, or clear the interrupt source, and write a ‘1’ to the corresponding Interrupt Source Flag. Writing a ‘1’ to the Interrupt Source Flag will cause the state machine to check the Interrupt Source to determine if the Interrupt Source Flag should clear or stay as a ‘1’. If the Condition to deassert is true, then the Interrupt Source Flag is cleared and nINT is also deasserted. If the Condition to deassert is false, then the Interrupt Source Flag remains set, and the nINT remains asserted. For example, setting the INT7 bit in the Interrupt Mask Register will enable the ENERGYON interrupt. After a cable is plugged in, the ENERGYON bit in the Mode Control/Status Register goes active and nINT will be asserted low. To de- assert the nINT interrupt output, either clear the ENERGYON bit in the Mode Control/Status Register by removing the cable and then writing a ‘1’ to the INT7 bit in the Interrupt Mask Register, OR clear the INT7 mask (bit 7 of the Interrupt Mask Register). TABLE 3-4: ALTERNATIVE INTERRUPT SYSTEM MANAGEMENT TABLE Event to Condition to Bit to Clear Mask Interrupt Source Flag Interrupt Source Assert nINT DeAssert nINT 30.8 29.8 WoL 3.32784.7:4 nPME Rising 3.32784.7:4 29.8 3.32784.7:4 all low or’ed 30.7 29.7 ENERGYON 17.1 ENERGYON Rising 17.1 17.1 low 29.7 30.6 29.6 Auto-Negotiation 1.5 Auto-Negotiate Rising 1.5 1.5 low 29.6 Complete Complete 30.5 29.5 Remote Fault 1.4 Remote Fault Rising 1.4 1.4 low 29.5 Detected 30.4 29.4 Link Down 1.2 Link Status Falling 1.2 1.2 high 29.4 30.3 29.3 Auto-Negotiation 5.14 Acknowledge Rising 5.14 5.14 low 29.3 LP Acknowledge 30.2 29.2 Parallel Detection 6.4 Parallel Detec- Rising 6.4 6.4 low 29.2 Fault tion Fault 30.1 29.1 Auto-Negotiation 6.1 Page Received Rising 6.1 6.1 low 29.1 Page Received Note: The ENERGYON bit in the Mode Control/Status Register is defaulted to a ‘1’ at the start of the signal acqui- sition process, therefore the INT7 bit in the Interrupt Mask Register will also read as a ‘1’ at power-up. If no signal is present, then both ENERGYON and INT7 will clear within a few milliseconds. DS00001987A-page 32  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 3.7 Configuration Straps Configuration straps allow various features of the device to be automatically configured to user defined values. Config- uration straps are latched upon Power-On Reset (POR) and pin reset (nRST). Configuration straps include internal resistors in order to prevent the signal from floating when unconnected. If a particular configuration strap is connected to a load, an external pull-up or pull-down resistor should be used to augment the internal resistor to ensure that it reaches the required voltage level prior to latching. The internal resistor can also be overridden by the addition of an external resistor. Note: The system designer must guarantee that configuration strap pins meet the timing requirements specified in Section 5.6.2, "Power-On nRST & Configuration Strap Timing". If configuration strap pins are not at the correct voltage level prior to being latched, the device may capture incorrect strap values. Note: When externally pulling configuration straps high, the strap should be tied to VDDIO, except for REGOFF and nINTSEL which should be tied to VDD2A. 3.7.1 PHYAD[2:0]: PHY ADDRESS CONFIGURATION The PHYAD[2:0] configuration straps are driven high or low to give each PHY a unique address. This address is latched into an internal register at the end of a hardware reset (default = 000b). In a multi-transceiver application (such as a repeater), the controller is able to manage each transceiver via the unique address. Each transceiver checks each man- agement data frame for a matching address in the relevant bits. When a match is recognized, the transceiver responds to that particular frame. The PHY address is also used to seed the scrambler. In a multi-transceiver application, this ensures that the scramblers are out of synchronization and disperses the electromagnetic radiation across the fre- quency spectrum. The device’s SMI address may be configured using hardware configuration to any value between 0 and 7. The user can configure the PHY address using Software Configuration if an address greater than 7 is required. The PHY address can be written (after SMI communication at some address is established) using the PHYAD bits of the Special Modes Reg- ister. The PHYAD[2:0] configuration straps are multiplexed with other signals as shown in Table 3-5. TABLE 3-5: PIN NAMES FOR ADDRESS BITS Address Bit Pin Name PHYAD[0] RXER/RXD4/PHYAD0 PHYAD[1] RXCLK/PHYAD1 PHYAD[2] RXD3/PHYAD2  2013-2015 Microchip Technology Inc. DS00001987A-page 33

LAN8740A/LAN8740Ai 3.7.2 MODE[2:0]: MODE CONFIGURATION The MODE[2:0] configuration straps control the configuration of the 10/100 digital block. When the nRST pin is deas- serted, the register bit values are loaded according to the MODE[2:0] configuration straps. The 10/100 digital block is then configured by the register bit values. When a soft reset occurs via the Soft Reset bit of the Basic Control Register, the configuration of the 10/100 digital block is controlled by the register bit values and the MODE[2:0] configuration straps have no affect. The device’s mode may be configured using the hardware configuration straps as summarized in Table 3-6. The user may configure the transceiver mode by writing the SMI registers. TABLE 3-6: MODE[2:0] BUS Default Register Bit Values MODE[2:0] Mode Definitions Register 0 Register 4 [13,12,10,8] [8,7,6,5] 000 10BASE-T Half Duplex. Auto-negotiation disabled. 0000 N/A 001 10BASE-T Full Duplex. Auto-negotiation disabled. 0001 N/A 010 100BASE-TX Half Duplex. Auto-negotiation disabled. 1000 N/A CRS is active during Transmit & Receive. 011 100BASE-TX Full Duplex. Auto-negotiation disabled. 1001 N/A CRS is active during Receive. 100 100BASE-TX Half Duplex is advertised. Auto-negoti- 1100 0100 ation enabled. CRS is active during Transmit & Receive. 101 Repeater mode. Auto-negotiation enabled. 1100 0100 100BASE-TX Half Duplex is advertised. CRS is active during Receive. 110 Power-Down mode. In this mode the transceiver will N/A N/A wake-up in Power-Down mode. The transceiver can- not be used when the MODE[2:0] bits are set to this mode. To exit this mode, the MODE bits in Register 18.7:5 (see Section 4.2.14, "Special Modes Register") must be configured to some other value and a soft reset must be issued. 111 All capable. Auto-negotiation enabled. X10X 1111 The MODE[2:0] hardware configuration pins are multiplexed with other signals as shown in Table 3-7. TABLE 3-7: PIN NAMES FOR MODE BITS MODE Bit Pin Name MODE[0] RXD0/MODE0 MODE[1] RXD1/MODE1 MODE[2] COL/CRS_DV/MODE2 3.7.3 RMIISEL: MII/RMII MODE CONFIGURATION MII or RMII mode selection is latched on the rising edge of the internal reset (nRST) based on the strapping of the RMIISEL configuration strap. The default mode is MII (via the internal pull-down resistor). To select RMII mode, pull the RMIISEL configuration strap high with an external resistor to VDDIO. When the nRST pin is deasserted, the MIIMODE bit of the Special Modes Register is loaded according to the RMIISEL configuration strap. The mode is reflected in the MIIMODE bit of the Special Modes Register. Refer to Section 3.4, "MAC Interface" for additional information on MII and RMII modes. DS00001987A-page 34  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 3.7.4 REGOFF: INTERNAL +1.2 V REGULATOR CONFIGURATION The incorporation of flexPWR technology provides the ability to disable the internal +1.2 V regulator. When the regulator is disabled, an external +1.2 V must be supplied to the VDDCR pin. Disabling the internal +1.2 V regulator makes it possible to reduce total system power, since an external switching regulator with greater efficiency (versus the internal linear regulator) can be used to provide +1.2 V to the transceiver circuitry. Note: Because the REGOFF configuration strap shares functionality with the LED1 pin, proper consideration must also be given to the LED polarity. Refer to Section 3.8.1, "LEDs" for additional information on the rela- tion between REGOFF and the LED1 polarity. 3.7.4.1 Disabling the Internal +1.2 V Regulator To disable the +1.2 V internal regulator, a pull-up strapping resistor should be connected from the REGOFF configura- tion strap to VDD2A. At power-on, after both VDDIO and VDD2A are within specification, the transceiver will sample REGOFF to determine whether the internal regulator should turn on. If the pin is sampled at a voltage greater than V , IH then the internal regulator is disabled and the system must supply +1.2 V to the VDDCR pin. The VDDIO voltage must be at least 80% of the operating voltage level (1.44 V when operating at 1.8 V, 2.0 V when operating at 2.5 V, 2.64 V when operating at 3.3 V) before voltage is applied to VDDCR. As described in Section3.7.4.2, when REGOFF is left floating or connected to VSS, the internal regulator is enabled and the system is not required to supply +1.2 V to the VDDCR pin. 3.7.4.2 Enabling the Internal +1.2 V Regulator The +1.2 V for VDDCR is supplied by the on-chip regulator unless the transceiver is configured for the regulator off mode using the REGOFF configuration strap as described in Section3.7.4.1. By default, the internal +1.2 V regulator is enabled when REGOFF is floating (due to the internal pull-down resistor). During power-on, if REGOFF is sampled below V , then the internal +1.2 V regulator will turn on and operate with power from the VDD2A pin. IL 3.7.5 nINTSEL: nINT/TXER/TXD4 CONFIGURATION The nINT, TXER, and TXD4 functions share a common pin. There are two functional modes for this pin, the TXER/TXD4 mode and nINT (interrupt) mode. The nINTSEL configuration strap is latched at POR and on the rising edge of the nRST. By default, nINTSEL is configured for nINT mode via the internal pull-up resistor. Note: In order to utilize EEE, the nINT/TXER/TXD4 pin must be configured as TXER/TXD4. Note: Due to the multiplexing of nINT and TXER on the same pin, when EEE and WoL are both enabled, nINT and/or nPME must be multiplexed on LED1 and/or LED2. Refer to Section 3.6, "Interrupt Management" and Section 3.8.4, "Wake on LAN (WoL)" for additional information. Note: Because the nINTSEL configuration strap shares functionality with the LED2 pin, proper consideration must also be given to the LED polarity. Refer to Section 3.8.1.6, "nINTSEL and LED2 Polarity Selection" for additional information on the relation between nINTSEL and the LED2 polarity.  2013-2015 Microchip Technology Inc. DS00001987A-page 35

LAN8740A/LAN8740Ai 3.8 Miscellaneous Functions 3.8.1 LEDS Two LED signals are provided as a convenient means to indicate the transceiver's mode of operation or be used as nINT or nPME signals. The LED1 and LED2 pin functions are configurable via the LED1 Function Select and LED2 Function Select bits of the Wakeup Control and Status Register (WUCSR), respectively. When used as an LED indicator, the LED signals are either active high or active low as described in Section 3.8.1.5, "REGOFF and LED1 Polarity Selec- tion" and Section 3.8.1.6, "nINTSEL and LED2 Polarity Selection". For additional information on nINT, refer to Section 3.6, "Interrupt Management". For additional information on nPME, refer to Section 3.8.4, "Wake on LAN (WoL)". When configured in the default Link/Activity mode, the LED1 output is driven active whenever the device detects a valid link, and blinks when CRS is active (high) indicating activity. When configured in the default Link Speed mode, the LED2 output is driven active when the operating speed is 100 Mbps. This LED will go inactive when the operating speed is 10 Mbps or during line isolation. Note: When pulling the LED1 and LED2 pins high, they must be tied to VDD2A, NOT VDDIO. Note: Due to the multiplexing of nINT and TXER on the same pin, when EEE and WoL are both enabled, nINT and/or nPME must be multiplexed on LED1 and/or LED2. Refer to Section 3.6, "Interrupt Management" and Section 3.8.4, "Wake on LAN (WoL)" for additional information. 3.8.1.1 LED1/nINT/nPME Usage with Internal Regulator Disabled (REGOFF High) When the LED1/nINT/nPME/REGOFF pin is high during reset, the internal regulator is disabled. After the deassertion of reset, this pin will first function as LED1 (Link Activity). Upon configuration, it can function as nINT or nPME. Figure 3-7 illustrates the steps required to program the LED1 pin as nINT or nPME with the internal regulator disabled. In this configuration, it is possible for an LED to be connected to this pin while it function as nINT or nPME during the WoL state. Since the polarity to turn on the LED is active low, the Link Activity LED will not be lit while waiting for a WoL event. Note: Refer to Section 3.7.4, "REGOFF: Internal +1.2 V Regulator Configuration" for additional information on the REGOFF configuration strap. FIGURE 3-7: LED1/nINT/nPME/REGOFF WITH INTERNAL REGULATOR DISABLED nRST Link Activity nINT/nPME Link Activity LED1/nINT/ nPME/REGOFF WUCSR[14:13] 00b 01b/10b 00b DS00001987A-page 36  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 3.8.1.2 LED1/nINT/nPME Usage with Internal Regulator Enabled (REGOFF Low) When the LED1/nINT/nPME/REGOFF pin is low during reset, the internal regulator is enabled. After the deassertion of reset, this pin will first function as LED1 (Link Activity). Upon configuration, it can function as nINT or nPME. Figure 3- 8 illustrates the steps required to program the LED1 pin as nINT or nPME with the internal regulator enabled. In this configuration, it is recommended not to connect an LED to this pin. Because this pin is active high, the LED will be lit while waiting for a WoL event. Note: Refer to Section 3.7.4, "REGOFF: Internal +1.2 V Regulator Configuration" for additional information on the REGOFF configuration strap. FIGURE 3-8: LED1/nINT/nPME/REGOFF WITH INTERNAL REGULATOR ENABLED nRST Link Activity nINT/nPME LED1/nINT/ nPME/REGOFF WUCSR[14:13] 00b 01b/10b 3.8.1.3 LED2/nINT/nPME Usage with nINTSEL Enabled When the LED2/nINT/nPME/nINTSEL pin is high during reset, the nINT/TXER/TXD4 pin is configured to function as nINT. After the deassertion of reset, this pin will first function as LED2 (Link Speed). Upon configuration, it can function as nPME. It is also possible to configure LED2 as nINT although this would duplicate the function of the nINT/TXER/TXD4 pin. Figure 3-9 illustrates the steps required to program the LED2 pin as nINT or nPME with nINTSEL enabled. In this configuration, it is possible for an LED be connected to this pin while it functions as nINT or nPME during a WoL state. Since the polarity to light the LED is active low, the Link Speed LED will not be lit while waiting for a WoL event. To provide further flexibility, LED2 can be reconfigured as Link Activity by writing 11b to the LED2 Function Select field of the Wakeup Control and Status Register (WUCSR). This allows LED2 to function as Link Activity when LED1 cannot be configured as Link Activity. Link Speed can be easily implemented on the microcontroller using GPIO. Note: Refer to Section 3.7.5, "nINTSEL: nINT/TXER/TXD4 Configuration" for additional information on the nINT- SEL configuration strap. FIGURE 3-9: LED2/nINT/nPME WITH nINTSEL ENABLED nRST Link Speed/ Link Speed/ nINT/nPME Link Activity Link Activity LED2/nINT/ nPME/nINTSEL WUCSR[12:11] 00b 00b/11b 01b/10b 00b/11b  2013-2015 Microchip Technology Inc. DS00001987A-page 37

LAN8740A/LAN8740Ai 3.8.1.4 LED2/nINT/nPME Usage with nINTSEL Disabled When the LED2/nINT/nPME/nINTSEL pin is low during reset, the nINT/TXER/TXD4 pin is configured to function as TXER/TXD4. After the deassertion of reset, this pin will first function as LED2. Upon configuration, it can function as nINT or nPME. Figure 3-10 illustrates the steps required to program the LED2 pin as nINT or nPME with nINTSEL dis- abled. In this configuration, it is not recommended to connect an LED to this pin. Because this pin is active high, the LED will be lit while waiting for a WoL event. FIGURE 3-10: LED2/nINT/nPME WITH nINTSEL DISABLED nRST Link Speed nINT/nPME LED2/nINT/ nPME/nINTSEL WUCSR[12:11] 00b 01b/10b 3.8.1.5 REGOFF and LED1 Polarity Selection The REGOFF configuration strap is shared with the LED1 pin. The LED1 output will automatically change polarity based on the presence of an external pull-up resistor. If the LED1 pin is pulled high to VDD2A by an external pull-up resistor to select a logical high for REGOFF, then the LED1 output will be active low. If the LED1 pin is pulled low by the internal pull-down resistor to select a logical low for REGOFF, the LED1 output will then be an active high output. Figure 3-11 details the LED1 polarity for each REGOFF configuration. FIGURE 3-11: LED1/REGOFF POLARITY CONFIGURATION REGOFF = 1 (Regulator OFF) REGOFF = 0 (Regulator ON) LED output = Active Low LED output = Active High VDD2A LED1/REGOFF 10K ~270  ~270  LED1/REGOFF Note: Refer to Section 3.7.4, "REGOFF: Internal +1.2 V Regulator Configuration" for additional information on the REGOFF configuration strap. DS00001987A-page 38  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 3.8.1.6 nINTSEL and LED2 Polarity Selection The nINTSEL configuration strap is shared with the LED2 pin. The LED2 output will automatically change polarity based on the presence of an external pull-down resistor. If the LED2 pin is pulled high to VDD2A to select a logical high for nINTSEL, then the LED2 output will be active low. If the LED2 pin is pulled low by an external pull-down resistor to select a logical low for nINTSEL, the LED2 output will then be an active high output. Figure 3-12 details the LED2 polarity for each nINTSEL configuration. FIGURE 3-12: LED2/nINTSEL POLARITY CONFIGURATION nINTSEL = 1 nINTSEL = 0 LED output = Active Low LED output = Active High VDD2A LED2/nINTSEL 10K ~270  ~270  LED2/nINTSEL Note: Refer to Section 3.7.5, "nINTSEL: nINT/TXER/TXD4 Configuration" for additional information on the nINT- SEL configuration strap. 3.8.2 VARIABLE VOLTAGE I/O The device’s digital I/O pins are variable voltage, allowing them to take advantage of low power savings from shrinking technologies. These pins can operate from a low I/O voltage of +1.8 V up to +3.3 V. The applied I/O voltage must main- tain its value with a tolerance of ±10%. Varying the voltage up or down after the transceiver has completed power-on reset can cause errors in the transceiver operation. Refer to Chapter 5, "Operational Characteristics" for additional infor- mation. Note: Input signals must not be driven high before power is applied to the device. 3.8.3 POWER-DOWN MODES There are two device power-down modes: General Power-Down Mode and Energy Detect Power-Down Mode. These modes are described in the following subsections. 3.8.3.1 General Power-Down This power-down mode is controlled via the Power Down bit of the Basic Control Register. In this mode, the entire trans- ceiver (except the management interface) is powered-down and remains in this mode as long as the Power Down bit is “1”. When the Power Down bit is cleared, the transceiver powers up and is automatically reset. 3.8.3.2 Energy Detect Power-Down (EDPD) This power-down mode is activated by setting the EDPWRDOWN bit of the Mode Control/Status Register. In this mode, when no energy is present on the line the transceiver is powered down (except for the management interface, the SQUELCH circuit, and the ENERGYON logic). The ENERGYON logic is used to detect the presence of valid energy from 100BASE-TX, 10BASE-T, or Auto-negotiation signals. In this mode, when the ENERGYON bit of the Mode Control/Status Register is low, the transceiver is powered-down and nothing is transmitted. When energy is received via link pulses or packets, the ENERGYON bit goes high and the transceiver powers-up. The device automatically resets into the state prior to power-down and asserts the nINT interrupt if the ENERGYON interrupt is enabled in the Interrupt Mask Register. The first and possibly the second packet to acti- vate ENERGYON may be lost. When the EDPWRDOWN bit of the Mode Control/Status Register is low, energy detect power-down is disabled.  2013-2015 Microchip Technology Inc. DS00001987A-page 39

LAN8740A/LAN8740Ai When in EDPD mode, the device’s NLP characteristics may be modified. The device can be configured to transmit NLPs in EDPD via the EDPD TX NLP Enable bit of the EDPD NLP/Crossover Time/EEE Configuration Register. When enabled, the TX NLP time interval is configurable via the EDPD TX NLP Interval Timer Select field of the EDPD NLP/Crossover Time/EEE Configuration Register. When in EDPD mode, the device can also be configured to wake on the reception of one or two NLPs. Setting the EDPD RX Single NLP Wake Enable bit of the EDPD NLP/Crossover Time/EEE Configuration Register will enable the device to wake on reception of a single NLP. If the EDPD RX Single NLP Wake Enable bit is cleared, the maximum interval for detecting reception of two NLPs to wake from EDPD is con- figurable via the EDPD RX NLP Max Interval Detect Select field of the EDPD NLP/Crossover Time/EEE Configuration Register. 3.8.4 WAKE ON LAN (WOL) The device supports PHY layer WoL event detection of Perfect DA, Broadcast, Magic Packet, and Wakeup frames. The WoL detection can be configured to assert the nINT interrupt pin or nPME pin, providing a mechanism for a system in sleep mode to return to an operational state when a WoL event occurs. This feature is particularly useful in addressing unnecessary waking of the main SoC in designs where the Ethernet MAC is integrated into the SoC. Each type of supported wake event (Perfect DA, Broadcast, Magic Packet, or Wakeup frames) may be individually enabled via Perfect DA Wakeup Enable (PFDA_EN), Broadcast Wakeup Enable (BCST_EN), Magic Packet Enable (MPEN), and Wakeup Frame Enable (WUEN) bits of the Wakeup Control and Status Register (WUCSR), respectively. Two methods are provided for indicating a WoL event to an external device: nINT and nPME. The nINT pin may be used to indicate WoL interrupt events by setting bit 8 (WoL) of the Interrupt Mask Register. Once enabled, any received packet that matches the condition(s) configured in the Wakeup Control and Status Register (WUCSR) will assert nINT until the interrupt is cleared. When using nINT to indicate a WoL interrupt, the pin may be shared with other non-WoL interrupt events, as configured via the Interrupt Mask Register. While waiting for a WoL event to occur, it is possible that other interrupts may be triggered. To prevent such conditions, all other interrupts shall be masked by system software, or the alternative nPME pin may be used. Refer to Section 3.6, "Interrupt Management" for additional nINT information. Alternatively, the nPME pin may be used to independently indicate WoL interrupt events. The nPME signal can be con- figured to output on any of the following pins: • LED1/nINT/nPME/nREGOFF • LED2/nINT/nPME/nINTSEL • RXD2/nPME/RMIISEL (Refer to Section 3.7.5, "nINTSEL: nINT/TXER/TXD4 Configuration" for configuration infor- mation) The LED1/nINT/nPME/nREGOFF or LED2/nINT/nPME/nINTSEL pin can be configured to function as nPME by config- uring the LED1 Function Select or LED2 Function Select bits of the Wakeup Control and Status Register (WUCSR) to 10b, respectively. The RXD2/nPME/RMIISEL pin can be configured to function as nPME by setting the RXD2/RMIISEL Function Select bit of the Wakeup Control and Status Register (WUCSR). The RXD2/nPME/RMIISEL pin can only be used as nPME when in RMII mode. Once the nPME pin is enabled, any received packet that matches the condition(s) configured in the Wakeup Control and Status Register (WUCSR) will assert nPME until WUCSR bits 7:4 are cleared by the system software. However, in some applications it may be desirable for nPME to self clear. When the nPME Self Clear bit of the Wakeup Control and Status Register (WUCSR) is set, the nPME pin will clear after the time configured in the Miscellaneous Configuration Register (MCFGR). Upon a WoL event, further resolution on the source of the event can be obtained by examining the Perfect DA Frame Received (PFDA_FR), Broadcast Frame Received (BCAST_FR), Magic Packet Received (MPR), and Remote Wakeup Frame Received (WUFR) status bits in the Wakeup Control and Status Register (WUCSR). Note: Due to the multiplexing of nINT and TXER on the same pin, when EEE and WoL are both enabled, nINT and/or nPME must be multiplexed on LED1 and/or LED2. The Wakeup Control and Status Register (WUCSR) also provides a WoL Configured bit, which may be set by software after all WoL registers are configured. Because all WoL related registers are not affected by software resets, software can poll the WoL Configured bit to ensure all WoL registers are fully configured. This allows the software to skip repro- gramming of the WoL registers after reboot due to a WoL event. The following subsections detail each type of WoL event. For additional information on the main system interrupts, refer to Section 3.6, "Interrupt Management". DS00001987A-page 40  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 3.8.4.1 Perfect DA (Destination Address) Detection When enabled, the Perfect DA detection mode allows the triggering of the nINT or nPME pin when a frame with the destination address matching the address stored in the MAC Receive Address A Register (RX_ADDRA), MAC Receive Address B Register (RX_ADDRB), and MAC Receive Address C Register (RX_ADDRC) is received. The frame must also pass the FCS and packet length check. As an example, the Host system must perform the following steps to enable the device to assert nINT on detection of a Perfect DA WoL event: 1. Set the desired MAC address to cause the wake event in the MAC Receive Address A Register (RX_ADDRA), MAC Receive Address B Register (RX_ADDRB), and MAC Receive Address C Register (RX_ADDRC). 2. Set the Perfect DA Wakeup Enable (PFDA_EN) bit of the Wakeup Control and Status Register (WUCSR) to enable Perfect DA detection. 3. Set bit 8 (WoL event indicator) in the Interrupt Mask Register to enable WoL events to trigger assertion of the nINT interrupt pin. When a match is triggered, the nINT interrupt pin will be asserted, bit 8 of the Interrupt Source Flag Register will be set, and the Perfect DA Frame Received (PFDA_FR) bit of the Wakeup Control and Status Register (WUCSR) will be set. Note: Alternatively, the LED1/nINT/nPME, LED2/nINT/nPME, or RXD2/nPME pin can be used to indicate a WoL event. Refer to Section 3.8.4, "Wake on LAN (WoL)" for additional information. 3.8.4.2 Broadcast Detection When enabled, the Broadcast detection mode allows the triggering of the nINT or nPME pin when a frame with the des- tination address value of FF FF FF FF FF FF is received. The frame must also pass the FCS and packet length check. As an example, the Host system must perform the following steps to enable the device to assert nINT on detection of a Broadcast WoL event: 1. Set the Broadcast Wakeup Enable (BCST_EN) bit of the Wakeup Control and Status Register (WUCSR) to enable Broadcast detection. 2. Set bit 8 (WoL event indicator) in the Interrupt Mask Register to enable WoL events to trigger assertion of the nINT interrupt pin. When a match is triggered, the nINT interrupt pin will be asserted, bit 8 of the Interrupt Source Flag Register will be set, and the Broadcast Frame Received (BCAST_FR) bit of the Wakeup Control and Status Register (WUCSR) will be set. Note: Alternatively, the LED1/nINT/nPME, LED2/nINT/nPME, or RXD2/nPME pin can be used to indicate a WoL event. Refer to Section 3.8.4, "Wake on LAN (WoL)" for additional information. 3.8.4.3 Magic Packet Detection When enabled, the Magic Packet detection mode allows the triggering of the nINT or nPME pin when a Magic Packet frame is received. A Magic Packet is a frame addressed to the device - either a unicast to the programmed address, or a broadcast - which contains the pattern 48’h FF_FF_FF_FF_FF_FF after the destination and source address field, fol- lowed by 16 repetitions of the desired MAC address (loaded into the MAC Receive Address A Register (RX_ADDRA), MAC Receive Address B Register (RX_ADDRB), and MAC Receive Address C Register (RX_ADDRC)) without any breaks or interruptions. In case of a break in the 16 address repetitions, the logic scans for the 48’h FF_FF_FF_FF_FF_FF pattern again in the incoming frame. The 16 repetitions may be anywhere in the frame but must be preceded by the synchronization stream. The frame must also pass the FCS check and packet length checking. As an example, if the desired address is 00h 11h 22h 33h 44h 55h, then the logic scans for the following data sequence in an Ethernet frame: Destination Address Source Address ……………FF FF FF FF FF FF 00 11 22 33 44 55 00 11 22 33 44 55 00 11 22 33 44 55 00 11 22 33 44 55 00 11 22 33 44 55 00 11 22 33 44 55 00 11 22 33 44 55 00 11 22 33 44 55 00 11 22 33 44 55 00 11 22 33 44 55 00 11 22 33 44 55 00 11 22 33 44 55 00 11 22 33 44 55 00 11 22 33 44 55 00 11 22 33 44 55 00 11 22 33 44 55 …FCS  2013-2015 Microchip Technology Inc. DS00001987A-page 41

LAN8740A/LAN8740Ai As an example, the Host system must perform the following steps to enable the device to assert nINT on detection of a Magic Packet WoL event: 1. Set the desired MAC address to cause the wake event in the MAC Receive Address A Register (RX_ADDRA), MAC Receive Address B Register (RX_ADDRB), and MAC Receive Address C Register (RX_ADDRC). 2. Set the Magic Packet Enable (MPEN) bit of the Wakeup Control and Status Register (WUCSR) to enable Magic Packet detection. 3. Set bit 8 (WoL event indicator) in the Interrupt Mask Register to enable WoL events to trigger assertion of the nINT interrupt pin. When a match is triggered, the nINT interrupt pin will be asserted, bit 8 of the Interrupt Source Flag Register will be set, and the Magic Packet Received (MPR) bit of the Wakeup Control and Status Register (WUCSR) will be set. Note: Alternatively, the LED1/nINT/nPME, LED2/nINT/nPME, or RXD2/nPME pin can be used to indicate a WoL event. Refer to Section 3.8.4, "Wake on LAN (WoL)" for additional information. 3.8.4.4 Wakeup Frame Detection When enabled, the Wakeup Frame detection mode allows the triggering of the nINT or nPME pin when a pre-pro- grammed Wakeup Frame is received. Wakeup Frame detection provides a way for system designers to detect a cus- tomized pattern within a packet via a programmable wake-up frame filter. The filter has a 128-bit byte mask that indicates which bytes of the frame should be compared by the detection logic. A CRC-16 is calculated over these bytes. The result is then compared with the filter’s respective CRC-16 to determine if a match exists. When a wake-up pattern is received, the Remote Wakeup Frame Received (WUFR) bit of the Wakeup Control and Status Register (WUCSR) is set. If enabled, the filter can also include a comparison between the frame’s destination address and the address specified in the MAC Receive Address A Register (RX_ADDRA), MAC Receive Address B Register (RX_ADDRB), and MAC Receive Address C Register (RX_ADDRC). The specified address can be a unicast or a multicast. If address matching is enabled, only the programmed unicast or multicast address will be considered a match. Non-specific multicast addresses and the broadcast address can be separately enabled. The address matching results are logically OR’d (i.e., specific address match result OR any multicast result OR broadcast result). Whether or not the filter is enabled and whether the destination address is checked is determined by configuring the Wakeup Filter Configuration Register A (WUF_CFGA). Before enabling the filter, the application program must provide the detection logic with the sample frame and corresponding byte mask. This information is provided by writing the Wakeup Filter Configuration Register A (WUF_CFGA), Wakeup Filter Configuration Register B (WUF_CFGB), and Wakeup Filter Byte Mask Registers (WUF_MASK). The starting offset within the frame and the expected CRC-16 for the filter is determined by the Filter Pattern Offset and Filter CRC-16 fields, respectively. If remote wakeup mode is enabled, the remote wakeup function checks each frame against the filter and recognizes the frame as a remote wakeup frame if it passes the filter’s address filtering and CRC value match. The pattern offset defines the location of the first byte that should be checked in the frame. The byte mask is a 128-bit field that specifies whether or not each of the 128 contiguous bytes within the frame, beginning with the pattern offset, should be checked. If bit j in the byte mask is set, the detection logic checks the byte (pattern offset + j) in the frame, otherwise byte (pattern offset + j) is ignored. At the completion of the CRC-16 checking process, the CRC-16 calculated using the pattern offset and byte mask is compared to the expected CRC-16 value associated with the filter. If a match occurs, a remote wake-up event is sig- naled. The frame must also pass the FCS check and packet length checking. Table 3-8 indicates the cases that produce a wake-up event. All other cases do not generate a wake-up event. TABLE 3-8: WAKEUP GENERATION CASES Address Frame Any MCAST BCAST Filter Enabled Frame Type CRC Matches Match Address Enabled Enabled Enabled Matches Yes Unicast Yes No X X X Yes Unicast Yes Yes X X Yes Yes Multicast Yes X Yes X X Yes Multicast Yes Yes No X Yes Yes Broadcast Yes X X Yes X DS00001987A-page 42  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai As an example, the Host system must perform the following steps to enable the device to assert nINT on detection of a Wakeup Frame WoL event: Declare Pattern: 1. Update the Wakeup Filter Byte Mask Registers (WUF_MASK) to indicate the valid bytes to match. 2. Calculate the CRC-16 value of valid bytes off-line and update the Wakeup Filter Configuration Register B (WUF_CFGB). CRC-16 is calculated as follows: At the start of a frame, CRC-16 is initialized with the value FFFFh. CRC-16 is updated when the pattern offset and mask indicate the received byte is part of the checksum calculation. The following algorithm is used to update the CRC-16 at that time: Let: ^ denote the exclusive or operator. Data [7:0] be the received data byte to be included in the checksum. CRC[15:0] contain the calculated CRC-16 checksum. F0 … F7 be intermediate results, calculated when a data byte is determined to be part of the CRC-16. Calculate: F0 = CRC[15] ^ Data[0] F1 = CRC[14] ^ F0 ^ Data[1] F2 = CRC[13] ^ F1 ^ Data[2] F3 = CRC[12] ^ F2 ^ Data[3] F4 = CRC[11] ^ F3 ^ Data[4] F5 = CRC[10] ^ F4 ^ Data[5] F6 = CRC[09] ^ F5 ^ Data[6] F7 = CRC[08] ^ F6 ^ Data[7] The CRC-32 is updated as follows: CRC[15] = CRC[7] ^ F7 CRC[14] = CRC[6] CRC[13] = CRC[5] CRC[12] = CRC[4] CRC[11] = CRC[3] CRC[10] = CRC[2] CRC[9] = CRC[1] ^ F0 CRC[8] = CRC[0] ^ F1 CRC[7] = F0 ^ F2 CRC[6] = F1 ^ F3 CRC[5] = F2 ^ F4 CRC[4] = F3 ^ F5 CRC[3] = F4 ^ F6 CRC[2] = F5 ^ F7 CRC[1] = F6 CRC[0] = F7 3. Determine the offset pattern with offset 0 being the first byte of the destination address. Update the offset in the Filter Pattern Offset field of the Wakeup Filter Configuration Register A (WUF_CFGA). Determine Address Matching Conditions: 4. Determine the address matching scheme based on Table 3-8 and update the Filter Broadcast Enable, Filter Any Multicast Enable, and Address Match Enable bits of the Wakeup Filter Configuration Register A (WUF_CFGA) accordingly. 5. If necessary (see step 4), set the desired MAC address to cause the wake event in the MAC Receive Address A Register (RX_ADDRA), MAC Receive Address B Register (RX_ADDRB), and MAC Receive Address C Register (RX_ADDRC). 6. Set the Filter Enable bit of the Wakeup Filter Configuration Register A (WUF_CFGA) to enable the filter.  2013-2015 Microchip Technology Inc. DS00001987A-page 43

LAN8740A/LAN8740Ai Enable Wakeup Frame Detection: 7. Set the Wakeup Frame Enable (WUEN) bit of the Wakeup Control and Status Register (WUCSR) to enable Wakeup Frame detection. 8. Set bit 8 (WoL event indicator) in the Interrupt Mask Register to enable WoL events to trigger assertion of the nINT interrupt pin. When a match is triggered, the nINT interrupt pin will be asserted and the Remote Wakeup Frame Received (WUFR) bit of the Wakeup Control and Status Register (WUCSR) will be set. To provide additional visibility to software, the Filter Triggered bit of the Wakeup Filter Configuration Register A (WUF_CFGA) will be set. Note: Alternatively, the LED1/nINT/nPME, LED2/nINT/nPME, or RXD2/nPME pin can be used to indicate a WoL event. Refer to Section 3.8.4, "Wake on LAN (WoL)" for additional information. 3.8.5 ENERGY EFFICIENT ETHERNET The device supports IEEE 802.3az Energy Efficient Ethernet (EEE). The EEE functionality is enabled/disabled via the PHY Energy Efficient Ethernet Enable (PHYEEEEN) bit of the EDPD NLP/Crossover Time/EEE Configuration Register. Energy Efficient Ethernet is disabled by default. In order for EEE to be utilized, the following conditions must be met: • The device must configured in MII mode (RMIISEL configuration strap low) • The nINT/TXER/TXD4 pin must be configured as TXER/TXD4 (nINTSEL configuration strap low) • EEE functionality must be enabled via the PHY Energy Efficient Ethernet Enable (PHYEEEEN) bit of the EDPD NLP/Crossover Time/EEE Configuration Register • The 100BASE-TX EEE bit of the MMD EEE Advertisement Register must be set • The selected MAC and link-partner must support and be configured for EEE operation • The device and link-partner must link in 100BASE-TX full-duplex mode The value of the PHY Energy Efficient Ethernet Enable (PHYEEEEN) bit affects the default values of the following reg- ister bits: • 100BASE-TX EEE bit of the MMD EEE Capability Register • 100BASE-TX EEE bit of the MMD EEE Advertisement Register Note: EEE cannot be used in RMII mode. Note: Due to the multiplexing of nINT and TXER on the same pin, when EEE and WoL are both enabled, nINT and/or nPME must be multiplexed on LED1 and/or LED2. Refer to Section 3.8.1, "LEDs" and Section 3.8.4, "Wake on LAN (WoL)" for additional information. 3.8.6 ISOLATE MODE The device data paths may be electrically isolated from the MII/RMII interface by setting the Isolate bit of the Basic Con- trol Register to “1”. In isolation mode, the transceiver does not respond to the TXD, TXEN and TXER inputs, but does respond to management transactions. Isolation provides a means for multiple transceivers to be connected to the same MII/RMII interface without contention. By default, the transceiver is not isolated (on power-up (Isolate=0). 3.8.7 RESETS The device provides two forms of reset: hardware and software. The device registers are reset by both hardware and software resets. Select register bits, indicated as “NASR” in the register definitions, are not cleared by a software reset. The registers are not reset by the power-down modes described in Section3.8.3. Note: For the first 16 µs after coming out of reset, the MII/RMII interface will run at 2.5 MHz. After this time, it will switch to 25 MHz if auto-negotiation is enabled. DS00001987A-page 44  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 3.8.7.1 Hardware Reset A hardware reset is asserted by driving the nRST input pin low. When driven, nRST should be held low for the minimum time detailed in Section 5.6.2, "Power-On nRST & Configuration Strap Timing" to ensure a proper transceiver reset. During a hardware reset, an external clock must be supplied to the XTAL1/CLKIN signal. Note: A hardware reset (nRST assertion) is required following power-up. Refer to Section 5.6.2, "Power-On nRST & Configuration Strap Timing" for additional information. 3.8.7.2 Software Reset A Software reset is activated by setting the Soft Reset bit of the Basic Control Register to “1”. All registers bits, except those indicated as “NASR” in the register definitions, are cleared by a Software reset. The Soft Reset bit is self-clearing. Per the IEEE 802.3u standard, clause 22 (22.2.4.1.1) the reset process will be completed within 0.5 s from the setting of this bit. 3.8.8 CARRIER SENSE The carrier sense (CRS) is output on the CRS pin in MII mode, and the CRS_DV pin in RMII mode. CRS is a signal defined by the MII specification in the IEEE 802.3u standard. The device asserts CRS based only on receive activity whenever the transceiver is either in repeater mode or full-duplex mode. Otherwise the transceiver asserts CRS based on either transmit or receive activity. The carrier sense logic uses the encoded, unscrambled data to determine carrier activity status. It activates carrier sense with the detection of 2 non-contiguous zeros within any 10 bit span. Carrier sense terminates if a span of 10 con- secutive ones is detected before a /J/K/ Start-of Stream Delimiter pair. If an SSD pair is detected, carrier sense is asserted until either /T/R/ End–of-Stream Delimiter pair or a pair of IDLE symbols is detected. Carrier is negated after the /T/ symbol or the first IDLE. If /T/ is not followed by /R/, then carrier is maintained. Carrier is treated similarly for IDLE followed by some non-IDLE symbol. 3.8.9 COLLISION DETECT A collision is the occurrence of simultaneous transmit and receive operations. The COL output is asserted to indicate that a collision has been detected. COL remains active for the duration of the collision. COL is changed asynchronously to both RXCLK and TXCLK. The COL output becomes inactive during full duplex mode. The COL may be tested by setting the Collision Test bit of the Basic Control Register to “1”. This enables the collision test. COL will be asserted within 512 bit times of TXEN rising and will be de-asserted within 4 bit times of TXEN falling. 3.8.10 LINK INTEGRITY TEST The device performs the link integrity test as outlined in the IEEE 802.3u (clause 24-15) Link Monitor state diagram. The link status is multiplexed with the 10 Mbps link status to form the Link Status bit in the Basic Status Register and to drive the LINK LED (LED1). The DSP indicates a valid MLT-3 waveform present on the RXP and RXN signals as defined by the ANSI X3.263 TP- PMD standard, to the Link Monitor state-machine, using the internal DATA_VALID signal. When DATA_VALID is asserted, the control logic moves into a Link-Ready state and waits for an enable from the auto-negotiation block. When received, the Link-Up state is entered, and the Transmit and Receive logic blocks become active. Should auto-negoti- ation be disabled, the link integrity logic moves immediately to the Link-Up state when the DATA_VALID is asserted. To allow the line to stabilize, the link integrity logic will wait a minimum of 330 ms from the time DATA_VALID is asserted until the Link-Ready state is entered. Should the DATA_VALID input be negated at any time, this logic will immediately negate the Link signal and enter the Link-Down state. When the 10/100 digital block is in 10BASE-T mode, the link status is derived from the 10BASE-T receiver logic.  2013-2015 Microchip Technology Inc. DS00001987A-page 45

LAN8740A/LAN8740Ai 3.8.11 CABLE DIAGNOSTICS The LAN8740A/LAN8740Ai provides cable diagnostics which allow for open/short and length detection of the Ethernet cable. The cable diagnostics consist of two primary modes of operation: • Time Domain Reflectometry (TDR) Cable Diagnostics TDR cable diagnostics enable the detection of open or shorted cabling on the TX or RX pair, as well as cable length estimation to the open/short fault. • Matched Cable Diagnostics Matched cable diagnostics enable cable length estimation on 100Mbps-linked cables. Refer to the following sub-sections for details on proper operation of each cable diagnostics mode. 3.8.11.1 Time Domain Reflectometry (TDR) Cable Diagnostics The LAN8740A/LAN8740Ai provides TDR cable diagnostics which enable the detection of open or shorted cabling on the TX or RX pair, as well as cable length estimation to the open/short fault. To utilize the TDR cable diagnostics, Auto- MDIX and Auto Negotiation must be disabled, and the LAN8740A/LAN8740Ai device must be forced to 100Mb full- duplex mode. These actions must be performed before setting the TDR Enable bit in the TDR Control/Status Register. With Auto-MDIX disabled, the TDR will test the TX or RX pair selected by register bit 27.15 (AMDIXCTRL). Proper cable testing should include a test of each pair. When TDR testing is complete, prior register settings may be restored. Figure 3-13 provides a flow diagram of proper TDR usage. DS00001987A-page 46  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai FIGURE 3-13: TDR USAGE FLOW DIAGRAM Start Disable ANEG and Force 100Mb Full- Duplex Write PHY Reg 0: 0x2100 Disable AMDIX and Force MDI (or MDIX) Write PHY Reg 27: 0x8000 (MDI) - OR - Write PHY Reg 27: 0xA000 (MDIX) Enable TDR Write PHY Reg 25: 0x8000 Check TDR Control/Status Register Read PHY Reg 25: 0x8000 NO Reg 25.8 == 0 TDR Channel Status Complete? YES Reg 25.8 == 1 Save: TDR Channel Type (Reg 25.10:9) TDR Channel Length (Reg 25.7:0) Repeat Testing in MDIX Mode MDIX Case Tested? YES Done  2013-2015 Microchip Technology Inc. DS00001987A-page 47

LAN8740A/LAN8740Ai The TDR operates by transmitting pulses on the selected twisted pair within the Ethernet cable (TX in MDI mode, RX in MDIX mode). If the pair being tested is open or shorted, the resulting impedance discontinuity results in a reflected signal that can be detected by the LAN8740A/LAN8740Ai. The LAN8740A/LAN8740Ai measures the time between the transmitted signal and received reflection and indicates the results in the TDR Channel Length field of the TDR Con- trol/Status Register. The TDR Channel Length field indicates the “electrical” length of the cable, and can be multiplied by the appropriate propagation constant in Table 3-9 to determine the approximate physical distance to the fault. Note: The TDR function is typically used when the link is inoperable. However, an active link will drop when oper- ating the TDR. Since the TDR relies on the reflected signal of an improperly terminated cable, there are several factors that can affect the accuracy of the physical length estimate. These include: 1. Cable Type (CAT 5, CAT5e, CAT6): The electrical length of each cable type is slightly different due to the twists- per-meter of the internal signal pairs and differences in signal propagation speeds. If the cable type is known, the length estimate can be calculated more accurately by using the propagation constant appropriate for the cable type (see Table 3-9). In many real-world applications the cable type is unknown, or may be a mix of different cable types and lengths. In this case, use the propagation constant for the “unknown” cable type. 2. TX and RX Pair: For each cable type, the EIA standards specify different twist rates (twists-per-meter) for each signal pair within the Ethernet cable. This results in different measurements for the RX and TX pair. 3. Actual Cable Length: The difference between the estimated cable length and actual cable length grows as the physical cable length increases, with the most accurate results at less than approximately 100m. 4. Open/Short Case: The Open and Shorted cases will return different TDR Channel Length values (electrical lengths) for the same physical distance to the fault. Compensation for this is achieved by using different propa- gation constants to calculate the physical length of the cable. For the Open case, the estimated distance to the fault can be calculated as follows: Distance to Open fault in meters TDR Channel Length * P OPEN Where: P is the propagation constant selected from Table 3-9. OPEN For the Shorted case, the estimated distance to the fault can be calculated as follows: Distance to Open fault in meters  TDR Channel Length * P SHORT Where: P is the propagation constant selected from Table 3-9. SHORT TABLE 3-9: TDR PROPAGATION CONSTANTS Cable Type TDR Propagation Constant Unknown CAT 6 CAT 5E CAT 5 P 0.769 0.745 0.76 0.85 OPEN P 0.793 0.759 0.788 0.873 SHORT DS00001987A-page 48  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai The typical cable length measurement margin of error for Open and Shorted cases is dependent on the selected cable type and the distance of the open/short from the device. Table 3-10 and Table 3-11 detail the typical measurement error for Open and Shorted cases, respectively. TABLE 3-10: TYPICAL MEASUREMENT ERROR FOR OPEN CABLE (+/- METERS) Selected Propagation Constant Physical Distance to Fault P = Unknown P = CAT 6 P = CAT 5E P = CAT 5 OPEN OPEN OPEN OPEN CAT 6 Cable, 9 6 0-100m CAT 5E Cable, 5 5 0-100m CAT 5 Cable, 13 3 0-100m CAT 6 Cable, 14 6 101-160m CAT 5E Cable, 8 6 101-160m CAT 5 Cable, 20 6 101-160m TABLE 3-11: TYPICAL MEASUREMENT ERROR FOR SHORTED CABLE (+/- METERS) Selected Propagation Constant Physical Distance to Fault P = Unknown PSHORT = PSHORT = PSHORT = SHORT CAT 6 CAT 5E CAT 5 CAT 6 Cable, 8 5 0-100m CAT 5E Cable, 5 5 0-100m CAT 5 Cable, 11 2 0-100m CAT 6 Cable, 14 6 101-160m CAT 5E Cable, 7 6 101-160m CAT 5 Cable, 11 3 101-160m  2013-2015 Microchip Technology Inc. DS00001987A-page 49

LAN8740A/LAN8740Ai 3.8.11.2 Matched Cable Diagnostics Matched cable diagnostics enable cable length estimation on 100Mbps-linked cables of up to 120 meters. If there is an active 100Mb link, the approximate distance to the link partner can be estimated using the Cable Length Register. If the cable is properly terminated, but there is no active 100Mb link (the link partner is disabled, nonfunctional, the link is at 10Mb, etc.), the cable length cannot be estimated and the Cable Length Register should be ignored. The estimated distance to the link partner can be determined via the Cable Length (CBLN) lookup table provided in Table 3-12. The typical cable length measurement margin of error for a matched cable case is +/- 20m. The matched cable length mar- gin of error is consistent for all cable types from 0 to 120m. TABLE 3-12: MATCH CASE ESTIMATED CABLE LENGTH (CBLN) LOOKUP TABLE CBLN Field Value Estimated Cable Length 0 - 3 0 4 6 5 17 6 27 7 38 8 49 9 59 10 70 11 81 12 91 13 102 14 113 15 123 Note: For a properly terminated cable (Match case), there is no reflected signal. In this case, the TDR Channel Length field is invalid and should be ignored. DS00001987A-page 50  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 3.8.12 LOOPBACK OPERATION The device may be configured for near-end loopback and far loopback. These loopback modes are detailed in the fol- lowing subsections. 3.8.12.1 Near-end Loopback Near-end loopback mode sends the digital transmit data back out the receive data signals for testing purposes, as indi- cated by the blue arrows in Figure 3-14. The near-end loopback mode is enabled by setting the Loopback bit of the Basic Control Register to “1”. A large percentage of the digital circuitry is operational in near-end loopback mode because data is routed through the PCS and PMA layers into the PMD sublayer before it is looped back. The COL signal will be inactive in this mode, unless Collision Test is enabled in the Basic Control Register. The transmitters are powered down regardless of the state of TXEN. Refer to Section 5.6.3.1, "100Mbps Internal Loopback MII Timing" for additional loopback timing information. FIGURE 3-14: NEAR-END LOOPBACK BLOCK DIAGRAM TXD TX 10/100 X CAT-5 Ethernet XFMR RXD RX MAC X Digital Analog Microchip Ethernet Transceiver 3.8.12.2 Far Loopback Far loopback is a special test mode for MDI (analog) loopback as indicated by the blue arrows in Figure 3-15. The far loopback mode is enabled by setting the FARLOOPBACK bit of the Mode Control/Status Register to “1”. In this mode, data that is received from the link partner on the MDI is looped back out to the link partner. The digital interface signals on the local MAC interface are isolated. Note: This special test mode is only available when operating in RMII mode. FIGURE 3-15: FAR LOOPBACK BLOCK DIAGRAM Far-end system TXD TX 10/100 X Link CAT-5 Ethernet XFMR RXD RX Partner MAC X Digital Analog Microchip Ethernet Transceiver  2013-2015 Microchip Technology Inc. DS00001987A-page 51

LAN8740A/LAN8740Ai 3.8.12.3 Connector Loopback The device maintains reliable transmission over very short cables and can be tested in a connector loopback as shown in Figure 3-16. An RJ45 loopback cable can be used to route the transmit signals from the output of the transformer back to the receiver inputs. The loopback works at both 10 and 100Mbps. FIGURE 3-16: CONNECTOR LOOPBACK BLOCK DIAGRAM 1 10/100 TXD TX 2 3 Ethernet XFMR 4 RXD RX 5 MAC 6 7 Digital Analog 8 Microchip RJ45 Loopback Cable. Created by connecting pin 1 to pin 3 Ethernet Transceiver and connecting pin 2 to pin 6. DS00001987A-page 52  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 3.9 Application Diagrams This section provides typical application diagrams for the following: • Simplified System Level Application Diagram • Power Supply Diagram (1.2 V Supplied by Internal Regulator) • Power Supply Diagram (1.2 V Supplied by External Source) • Twisted-Pair Interface Diagram (Single Power Supply) • Twisted-Pair Interface Diagram (Dual Power Supplies) 3.9.1 SIMPLIFIED SYSTEM LEVEL APPLICATION DIAGRAM FIGURE 3-17: SIMPLIFIED SYSTEM LEVEL APPLICATION DIAGRAM LAN8740A/LAN8740Ai 10/100 PHY 32-VQFN MII MII MDIO MDC nINT Mag RJ45 TXD[3:0] TXP 4 TXN TXCLK TXER RXP TXEN RXN RXD[3:0] 4 RXCLK RXDV XTAL1/CLKIN 25 MHz LED[2:1] XTAL2 2 nRST Interface  2013-2015 Microchip Technology Inc. DS00001987A-page 53

LAN8740A/LAN8740Ai 3.9.2 POWER SUPPLY DIAGRAM (1.2 V SUPPLIED BY INTERNAL REGULATOR) FIGURE 3-18: POWER SUPPLY DIAGRAM (1.2 V SUPPLIED BY INTERNAL REGULATOR) LAN8740A/LAN8740Ai 32-VQFN Power Supply 3.3 V Ch.2: 3.3 V Core Logic Circuitry VDDCR Internal VDD2A OUT IN Regulator 1 uF 470 pF C BYPASS VDDDIO VDD1A VDDIO Ch.1: 3.3 V Supply Circuitry 1.8 - 3.3 V C C C BYPASS F BYPASS RBIAS LED1/ REGOFF VSS 12.1k ~270 Ohm DS00001987A-page 54  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 3.9.3 POWER SUPPLY DIAGRAM (1.2 V SUPPLIED BY EXTERNAL SOURCE) FIGURE 3-19: POWER SUPPLY DIAGRAM (1.2 V SUPPLIED BY EXTERNAL SOURCE) LAN8740A/LAN8740Ai 32-VQFN Power Supply 3.3 V Ch.2: 3.3 V Core Logic Circuitry VDDCR VDDCR Internal VDD2A Supply OUTRegulator IN 1.2 V 1 uF 470 pF (Disabled) C BYPASS VDDDIO VDD1A VDDIO Ch.1: 3.3 V Supply Circuitry 1.8 - 3.3 V C C C BYPASS F BYPASS RBIAS LED1/ REGOFF VSS 12.1k ~270 Ohm 10k  2013-2015 Microchip Technology Inc. DS00001987A-page 55

LAN8740A/LAN8740Ai 3.9.4 TWISTED-PAIR INTERFACE DIAGRAM (SINGLE POWER SUPPLY) FIGURE 3-20: TWISTED-PAIR INTERFACE DIAGRAM (SINGLE POWER SUPPLY) Ferrite LAN8740A/LAN8740Ai Bead 32-VQFN SPuopwpelry 49.9 OhmResistors 3.3 V VDD2A CBYPASS VDD1A CBYPASS Magnetics RJ45 TXP 1 2 75 Ohm 3 4 5 6 TXN 7 8 RXP 75 Ohm RXN 1000 pF 3 kV CBYPASS DS00001987A-page 56  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 3.9.5 TWISTED-PAIR INTERFACE DIAGRAM (DUAL POWER SUPPLIES) FIGURE 3-21: TWISTED-PAIR INTERFACE DIAGRAM (DUAL POWER SUPPLIES) LAN8740A/LAN8740Ai Power 49.9 Ohm Resistors Power 32-VQFN Supply Supply 3.3 V 2.5 V - 3.3 V VDD2A CBYPASS VDD1A CBYPASS Magnetics RJ45 TXP 1 2 75 Ohm 3 4 5 6 TXN 7 8 RXP 75 Ohm RXN 1000 pF 3 kV CBYPASS  2013-2015 Microchip Technology Inc. DS00001987A-page 57

LAN8740A/LAN8740Ai 4.0 REGISTER DESCRIPTIONS This chapter describes the various Control and Status Registers (CSRs) and MDIO Manageable Device (MMD) Regis- ters. The CSRs follow the IEEE 802.3 (clause 22.2.4) management register set. The MMD registers adhere to the IEEE 802.3-2008 45.2 MDIO Interface Registers specification. All functionality and bit definitions comply with these stan- dards. The IEEE 802.3 specified register index (in decimal) is included with each CSR definition, allowing for addressing of these registers via the Serial Management Interface (SMI) protocol. MMD registers are accessed indirectly via the MMD Access Control Register and MMD Access Address/Data Register CSRs. 4.1 Register Nomenclature Table 4-1 describes the register bit attribute notation used throughout this document. TABLE 4-1: REGISTER BIT TYPES Register Bit Type Notation Register Bit Description R Read: A register or bit with this attribute can be read. W Write: A register or bit with this attribute can be written. RO Read only: Writes have no effect. WO Write only: If a register or bit is write-only, reads will return unspecified data. WC Write One to Clear: Writing a one clears the value. Writing a zero has no effect WAC Write Anything to Clear: Writing anything clears the value. RC Read to Clear: Contents is cleared after the read. Writes have no effect. LL Latch Low: Clear on read of register. LH Latch High: Clear on read of register. SC Self-Clearing: Contents are self-cleared after the being set. Writes of zero have no effect. Contents can be read. SS Self-Setting: Contents are self-setting after being cleared. Writes of one have no effect. Contents can be read. RO/LH Read Only, Latch High: Bits with this attribute will stay high until the bit is read. After it is read, the bit will either remain high if the high condition remains, or will go low if the high condition has been removed. If the bit has not been read, the bit will remain high regardless of a change to the high condition. This mode is used in some Ethernet PHY registers. NASR Not Affected by Software Reset: The state of NASR bits do not change on assertion of a software reset. RESERVED Reserved Field: Reserved fields must be written with zeros to ensure future compati- bility. The value of reserved bits is not guaranteed on a read. Many of these register bit notations can be combined. Some examples of this are shown below: • R/W: Can be written. Will return current setting on a read. • R/WAC: Will return current setting on a read. Writing anything clears the bit. DS00001987A-page 58  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 4.2 Control and Status Registers Table 4-2 provides a list of supported registers. Register details, including bit definitions, are provided in the proceeding subsections. TABLE 4-2: SMI REGISTER MAP Register Index Register Name Group (Decimal) 0 Basic Control Register Basic 1 Basic Status Register Basic 2 PHY Identifier 1 Register Extended 3 PHY Identifier 2 Register Extended 4 Auto Negotiation Advertisement Register Extended 5 Auto Negotiation Link Partner Ability Register Extended 6 Auto Negotiation Expansion Register Extended 7 Auto Negotiation Next Page TX Register Extended 8 Auto Negotiation Next Page RX Register Extended 13 MMD Access Control Register Extended 14 MMD Access Address/Data Register Extended 16 EDPD NLP/Crossover Time/EEE Configuration Register Vendor-specific 17 Mode Control/Status Register Vendor-specific 18 Special Modes Register Vendor-specific 24 TDR Patterns/Delay Control Register Vendor-specific 25 TDR Control/Status Register Vendor-specific 26 Symbol Error Counter Register Vendor-specific 27 Special Control/Status Indications Register Vendor-specific 28 Cable Length Register Vendor-specific 29 Interrupt Source Flag Register Vendor-specific 30 Interrupt Mask Register Vendor-specific 31 PHY Special Control/Status Register Vendor-specific  2013-2015 Microchip Technology Inc. DS00001987A-page 59

LAN8740A/LAN8740Ai 4.2.1 BASIC CONTROL REGISTER Index (In Decimal): 0 Size: 16 bits Bits Description Type Default 15 Soft Reset R/W 0b 1 = Software reset. Bit is self-clearing. When setting this bit do not set other SC bits in this register. Note: The configuration (as described in Section 3.7.2, "MODE[2:0]: Mode Configuration") is set from the register bit values, and not from the mode pins. 14 Loopback R/W 0b 0 = Normal operation 1 = Loopback mode 13 Speed Select R/W (see Note 1) 0 = 10 Mbps 1 = 100 Mbps Note: Ignored if auto-negotiation is enabled (0.12 = 1). 12 Auto-Negotiation Enable R/W (see Note 1) 0 = Disable auto-negotiate process 1 = Enable auto-negotiate process (overrides 0.13 and 0.8) 11 Power Down R/W 0b 0 = Normal operation 1 = General power down mode 10 Isolate R/W 0b 0 = Normal operation 1 = Electrical isolation of PHY from the MII/RMII 9 Restart Auto-Negotiate R/W 0b 0 = Normal operation SC 1 = Restart auto-negotiate process Note: Bit is self-clearing. 8 Duplex Mode R/W (see Note 1) 0 = Half duplex 1 = Full duplex Note: Ignored if Auto-Negotiation is enabled (0.12 = 1). 7 Collision Test R/W 0b 0 = Disable COL test 1 = Enable COL test 6:0 RESERVED RO - Note1: The default value of this bit is determined by the MODE[2:0] configuration straps. Refer to Section 3.7.2, "MODE[2:0]: Mode Configuration" for additional information. DS00001987A-page 60  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 4.2.2 BASIC STATUS REGISTER Index (In Decimal): 1 Size: 16 bits Bits Description Type Default 15 100BASE-T4 RO 0b 0 = No T4 ability 1 = T4 able 14 100BASE-TX Full Duplex RO 1b 0 = No TX full duplex ability 1 = TX with full duplex 13 100BASE-TX Half Duplex RO 1b 0 = No TX half duplex ability 1 = TX with half duplex 12 10BASE-T Full Duplex RO 1b 0 = No 10 Mbps with full duplex ability 1 = 10 Mbps with full duplex 11 10BASE-T Half Duplex RO 1b 0 = No 10 Mbps with half duplex ability 1 = 10 Mbps with half duplex 10 100BASE-T2 Full Duplex RO 0b 0 = PHY is not able to perform full duplex 100BASE-T2 1 = PHY is able to perform full duplex 100BASE-T2 9 100BASE-T2 Half Duplex RO 0b 0 = PHY is not able to perform half duplex 100BASE-T2 1 = PHY is able to perform half duplex 100BASE-T2 8 Extended Status RO 0b 0 = No extended status information in register 15 1 = Extended status information in register 15 7:6 RESERVED RO - 5 Auto-Negotiate Complete RO 0b 0 = Auto-negotiate process not completed 1 = Auto-negotiate process completed 4 Remote Fault RO/LH 0b 1 = Remote fault condition detected 0 = No remote fault 3 Auto-Negotiate Ability RO 1b 0 = Unable to perform auto-negotiation function 1 = Able to perform auto-negotiation function 2 Link Status RO/LL 0b 0 = Link is down. 1 = Link is up. 1 Jabber Detect RO/LH 0b 0 = No jabber condition detected. 1 = Jabber condition detected. 0 Extended Capabilities RO 1b 0 = Does not support extended capabilities registers 1 = Supports extended capabilities registers  2013-2015 Microchip Technology Inc. DS00001987A-page 61

LAN8740A/LAN8740Ai 4.2.3 PHY IDENTIFIER 1 REGISTER Index (In Decimal): 2 Size: 16 bits Bits Description Type Default 15:0 PHY ID Number R/W 0007h Assigned to the 3rd through 18th bits of the Organizationally Unique Identifier (OUI), respectively. DS00001987A-page 62  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 4.2.4 PHY IDENTIFIER 2 REGISTER Index (In Decimal): 3 Size: 16 bits Bits Description Type Default 15:10 PHY ID Number R/W C110h Assigned to the 19th through 24th bits of the OUI. 9:4 Model Number R/W Six-bit manufacturer’s model number 3:0 Revision Number R/W Four-bit manufacturer’s revision number Note: The default value of the Revision Number field may vary dependent on the silicon revision number.  2013-2015 Microchip Technology Inc. DS00001987A-page 63

LAN8740A/LAN8740Ai 4.2.5 AUTO NEGOTIATION ADVERTISEMENT REGISTER Index (In Decimal): 4 Size: 16 bits Bits Description Type Default 15 Next Page R/W 0b 0 = No next page ability 1 = Next page capable 14 RESERVED RO - 13 Remote Fault R/W 0b 0 = No remote fault 1 = Remote fault detected 12 RESERVED RO - 11:10 Pause Operation R/W 00b 00 = No PAUSE 01 = Symmetric PAUSE 10 = Asymmetric PAUSE toward link partner 11 = Advertise support for both Symmetric PAUSE and Asymmetric PAUSE toward local device Note: When both symmetric PAUSE and asymmetric PAUSE are set, the device will only be configured to, at most, one of the two settings upon auto-negotiation completion. 9 RESERVED RO - 8 100BASE-TX Full Duplex R/W (see Note 1) 0 = No TX full duplex ability 1 = TX with full duplex 7 100BASE-TX R/W 1b 0 = No TX ability 1 = TX able 6 10BASE-T Full Duplex R/W (see Note 1) 0 = No 10 Mbps with full duplex ability 1 = 10 Mbps with full duplex 5 10BASE-T R/W (see Note 1) 0 = No 10 Mbps ability 1 = 10 Mbps able 4:0 Selector Field R/W 00001b 00001 = IEEE 802.3 Note1: The default value of this bit is determined by the MODE[2:0] configuration straps. Refer to Section 3.7.2, "MODE[2:0]: Mode Configuration" for additional information. DS00001987A-page 64  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 4.2.6 AUTO NEGOTIATION LINK PARTNER ABILITY REGISTER Index (In Decimal): 5 Size: 16 bits Bits Description Type Default 15 Next Page RO 0b 0 = No next page ability 1 = Next page capable 14 Acknowledge RO 0b 0 = Link code word not yet received 1 = Link code word received from partner 13 Remote Fault RO 0b 0 = No remote fault 1 = Remote fault detected 12 RESERVED RO - 11:10 Pause Operation RO 00b 00 = No PAUSE supported by partner station 01 = Symmetric PAUSE supported by partner station 10 = Asymmetric PAUSE supported by partner station 11 = Both Symmetric PAUSE and Asymmetric PAUSE supported by partner station 9 100BASE-T4 RO 0b 0 = No T4 ability 1 = T4 able Note: This device does not support T4 ability. 8 100BASE-TX Full Duplex RO 0b 0 = No TX full duplex ability 1 = TX with full duplex 7 100BASE-TX RO 0b 0 = No TX ability 1 = TX able 6 10BASE-T Full Duplex RO 0b 0 = No 10 Mbps with full duplex ability 1 = 10 Mbps with full duplex 5 10BASE-T RO 0b 0 = No 10 Mbps ability 1 = 10 Mbps able 4:0 Selector Field RO 00001b 00001 = IEEE 802.3  2013-2015 Microchip Technology Inc. DS00001987A-page 65

LAN8740A/LAN8740Ai 4.2.7 AUTO NEGOTIATION EXPANSION REGISTER Index (In Decimal): 6 Size: 16 bits Bits Description Type Default 15:7 RESERVED RO - 6 Receive Next Page Location Able RO 1b 0 = Received next page storage location is not specified by bit 6.5 1 = Received next page storage location is specified by bit 6.5 5 Received Next Page Storage Location RO 1b 0 = Link partner next pages are stored in the Auto Negotiation Link Partner Ability Register (PHY register 5) 1 = Link partner next pages are stored in the Auto Negotiation Next Page RX Register (PHY register 8) 4 Parallel Detection Fault RO/LH 0b 0 = No fault detected by parallel detection logic 1 = Fault detected by parallel detection logic 3 Link Partner Next Page Able RO 0b 0 = Link partner does not have next page ability. 1 = Link partner has next page ability. 2 Next Page Able RO 1b 0 = Local device does not have next page ability. 1 = Local device has next page ability. 1 Page Received RO/LH 0b 0 = New page not yet received 1 = New page received 0 Link Partner Auto-Negotiation Able RO 0b 0 = Link partner does not have auto-negotiation ability. 1 = Link partner has auto-negotiation ability. DS00001987A-page 66  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 4.2.8 AUTO NEGOTIATION NEXT PAGE TX REGISTER Index (In Decimal): 7 Size: 16 bits Bits Description Type Default 15 Next Page R/W 0b 0 = No next page ability 1 = Next page capable 14 RESERVED RO - 13 Message Page R/W 1b 0 = Unformatted page 1 = Message page 12 Acknowledge 2 R/W 0b 0 = Device cannot comply with message. 1 = Device will comply with message. 11 Toggle RO 0b 0 = Previous value was HIGH. 1 = Previous value was LOW. 10:0 Message Code R/W 000 Message/Unformatted Code Field 0000 0001b  2013-2015 Microchip Technology Inc. DS00001987A-page 67

LAN8740A/LAN8740Ai 4.2.9 AUTO NEGOTIATION NEXT PAGE RX REGISTER Index (In Decimal): 8 Size: 16 bits Bits Description Type Default 15 Next Page RO 0b 0 = No next page ability 1 = Next page capable 14 Acknowledge RO 0b 0 = Link code word not yet received from partner 1 = Link code word received from partner 13 Message Page RO 0b 0 = Unformatted page 1 = Message page 12 Acknowledge 2 RO 0b 0 = Device cannot comply with message. 1 = Device will comply with message. 11 Toggle RO 0b 0 = Previous value was HIGH. 1 = Previous value was LOW. 10:0 Message Code RO 000 Message/Unformatted Code Field 0000 0000b DS00001987A-page 68  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 4.2.10 MMD ACCESS CONTROL REGISTER Index (In Decimal): 13 Size: 16 bits This register in conjunction with the MMD Access Address/Data Register provides indirect access to the MDIO Man- ageable Device (MMD) registers. Refer to Section 4.3, "MDIO Manageable Device (MMD) Registers" for additional details. Bits Description Type Default 15:14 MMD Function R/W 00b This field is used to select the desired MMD function: 00 = Address 01 = Data, no post increment 10 = RESERVED 11 = RESERVED 13:5 RESERVED RO - 4:0 MMD Device Address (DEVAD) R/W 0h This field is used to select the desired MMD device address. (3=PCS, 7=auto-negotiation)  2013-2015 Microchip Technology Inc. DS00001987A-page 69

LAN8740A/LAN8740Ai 4.2.11 MMD ACCESS ADDRESS/DATA REGISTER Index (In Decimal): 14 Size: 16 bits This register in conjunction with the MMD Access Control Register provides indirect access to the MDIO Manageable Device (MMD) registers. Refer to Section 4.3, "MDIO Manageable Device (MMD) Registers" for additional details. Bits Description Type Default 15:0 MMD Register Address/Data R/W 0000h If the MMD Function field of the MMD Access Control Register is “00”, this field is used to indicate the MMD register address to read/write of the device specified in the MMD Device Address (DEVAD) field. Otherwise, this register is used to read/write data from/to the previously specified MMD address. DS00001987A-page 70  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 4.2.12 EDPD NLP/CROSSOVER TIME/EEE CONFIGURATION REGISTER Index (In Decimal): 16 Size: 16 bits Bits Description Type Default 15 EDPD TX NLP Enable R/W 0b When in Energy Detect Power-Down (EDPD) mode (EDPWRDOWN=1), this NASR bit enables the transmission of single TX NLPs at the interval defined by the EDPD TX NLP Interval Timer Select field. 0 = TX NLP disabled 1 = TX NLP enabled when in EDPD mode 14:13 EDPD TX NLP Interval Timer Select R/W 00b When in Energy Detect Power-Down (EDPD) mode (EDPWRDOWN=1) and NASR EDPD TX NLP Enable is 1, this field defines the interval used to send single TX NLPs. 00 = 1 second (default) 01 = 768 ms 10 = 512 ms 11 = 256 ms 12 EDPD RX Single NLP Wake Enable R/W 0b When in Energy Detect Power-Down (EDPD) mode (EDPWRDOWN=1), this NASR bit enables waking the PHY on reception of a single RX NLP. 0 = RX NLP wake disabled 1 = TX NLP wake enabled when in EDPD mode 11:10 EDPD RX NLP Max Interval Detect Select R/W 00b When in Energy Detect Power-Down (EDPD) mode (EDPWRDOWN=1) and NASR EDPD RX Single NLP Wake Enable is 0, this field defines the maximum inter- val for detecting two RX NLPs to wake from EDPD mode 00 = 64 ms (default) 01 = 256 ms 10 = 512 ms 11 = 1 second 9:3 RESERVED RO - 2 PHY Energy Efficient Ethernet Enable (PHYEEEEN) R/W 0b When set, enables Energy Efficient Ethernet (EEE) operation in the PHY. NASR When cleared, EEE operation is disabled. Refer to Section 3.8.5, "Energy Efficient Ethernet" for additional information. 1 EDPD Extend Crossover R/W 0b When in Energy Detect Power-Down (EDPD) mode (EDPWRDOWN=1), NASR setting this bit to 1 extends the crossover time by 2976 ms. 0 = Crossover time extension disabled 1 = Crossover time extension enabled (2976 ms) 0 Extend Manual 10/100 Auto-MDIX Crossover Time R/W 1b When Auto-MIDX is enabled and the PHY is in manual 10BASE-T or NASR 100BASE-TX mode, setting this bit to 1 extends the crossover time by 1984 ms to allow linking to an auto-negotiation link partner PHY. 0 = Crossover time extension disabled 1 = Crossover time extension enabled (1984 ms)  2013-2015 Microchip Technology Inc. DS00001987A-page 71

LAN8740A/LAN8740Ai 4.2.13 MODE CONTROL/STATUS REGISTER Index (In Decimal): 17 Size: 16 bits Bits Description Type Default 15:14 RESERVED RO - 13 EDPWRDOWN R/W 0b Enable the Energy Detect Power-Down (EDPD) mode: 0 = Energy Detect Power-Down is disabled. 1 = Energy Detect Power-Down is enabled. Note: When in EDPD mode, the device’s NLP characteristics can be modified via the EDPD NLP/Crossover Time/EEE Configuration Register. 12:10 RESERVED RO - 9 FARLOOPBACK R/W 0b Enables far loopback mode (i.e., all the received packets are sent back simul- taneously (in 100BASE-TX only)). This bit is only active in RMII mode. This mode works even if the Isolate bit (0.10) is set. 0 = Far loopback mode is disabled. 1 = Far loopback mode is enabled. Refer to Section 3.8.12.2, "Far Loopback" for additional information. 8:7 RESERVED RO - 6 ALTINT R/W 0b Alternate Interrupt Mode: 0 = Primary interrupt system enabled (Default) 1 = Alternate interrupt system enabled Refer to Section 3.6, "Interrupt Management" for additional information. 5:2 RESERVED RO - 1 ENERGYON RO 1b Indicates whether energy is detected. This bit transitions to “0” if no valid energy is detected within 256 ms. It is reset to “1” by a hardware reset and is unaffected by a software reset. Refer to Section 3.8.3.2, "Energy Detect Power-Down (EDPD)" for additional information. 0 RESERVED R/W 0b DS00001987A-page 72  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 4.2.14 SPECIAL MODES REGISTER Index (In Decimal): 18 Size: 16 bits Bits Description Type Default 15 RESERVED RO - 14 MIIMODE RO (see Note 1) Reflects the mode of the digital interface: 0 = MII mode 1 = RMII mode 13:8 RESERVED RO - 7:5 MODE R/W (see Note 2) Transceiver mode of operation. Refer to Section 3.7.2, "MODE[2:0]: Mode NASR Configuration" for additional details. 4:0 PHYAD R/W (see Note 3) PHY Address. The PHY Address is used for the SMI address and for initializa- NASR tion of the Cipher (Scrambler) key. Refer to Section 3.7.1, "PHYAD[2:0]: PHY Address Configuration" for additional details. Note1: The default value of this field is determined by the RMIISEL configuration strap. Refer to Section 3.7.3, "RMIISEL: MII/RMII Mode Configuration" for additional information. 2: The default value of this field is determined by the MODE[2:0] configuration straps. Refer to Section 3.7.2, "MODE[2:0]: Mode Configuration" for additional information. 3: The default value of this field is determined by the PHYAD[0] configuration strap. Refer to Section 3.7.1, "PHYAD[2:0]: PHY Address Configuration" for additional information.  2013-2015 Microchip Technology Inc. DS00001987A-page 73

LAN8740A/LAN8740Ai 4.2.15 TDR PATTERNS/DELAY CONTROL REGISTER Index (In Decimal): 24 Size: 16 bits Bits Description Type Default 15 TDR Delay In R/W 0b 0 = Line break time is 2ms. NASR 1 = The device uses TDR Line Break Counter to increase the line break time before starting TDR. 14:12 TDR Line Break Counter R/W 000b When TDR Delay In is 1, this field specifies the increase in line break time in NASR increments of 256ms, up to 2 seconds. 11:6 TDR Pattern High R/W 101110b This field specifies the data pattern sent in TDR mode for the high cycle. NASR 5:0 TDR Pattern Low R/W 011101b This field specifies the data pattern sent in TDR mode for the low cycle. NASR DS00001987A-page 74  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 4.2.16 TDR CONTROL/STATUS REGISTER Index (In Decimal): 25 Size: 16 bits Bits Description Type Default 15 TDR Enable R/W 0b 0 = TDR mode disabled NASR 1 = TDR mode enabled SC Note: This bit self clears when TDR completes (TDR Channel Status goes high) 14 TDR Analog to Digital Filter Enable R/W 0b 0 = TDR analog to digital filter disabled NASR 1 = TDR analog to digital filter enabled (reduces noise spikes during TDR pulses) 13:11 RESERVED RO - 10:9 TDR Channel Cable Type R/W 00b Indicates the cable type determined by the TDR test. NASR 00 = Default 01 = Shorted cable condition 10 = Open cable condition 11 = Match cable condition 8 TDR Channel Status R/W 0b When high, this bit indicates that the TDR operation has completed. This bit NASR will stay high until reset or the TDR operation is restarted (TDR Enable = 1) 7:0 TDR Channel Length R/W 00h This eight bit value indicates the TDR channel length during a short or open NASR cable condition. Refer to Section 3.8.11.1, "Time Domain Reflectometry (TDR) Cable Diagnostics" for additional information on the usage of this field. Note: This field is not valid during a match cable condition. The Cable Length Register must be used to determine cable length during a non-open/short (match) condition. Refer to Section 3.8.11, "Cable Diagnostics" for additional information.  2013-2015 Microchip Technology Inc. DS00001987A-page 75

LAN8740A/LAN8740Ai 4.2.17 SYMBOL ERROR COUNTER REGISTER Index (In Decimal): 26 Size: 16 bits Bits Description Type Default 15:0 Symbol Error Counter (SYM_ERR_CNT) RO 0000h This 100BASE-TX receiver-based error counter increments when an invalid code symbol is received, including IDLE symbols. The counter is incremented only once per packet, even when the received packet contains more than one symbol error. This field counts up to 65,536 and rolls over to 0 if incremented beyond it’s maximum value. Note: This register is cleared on reset, but is not cleared by reading the register. It does not increment in 10BASE-T mode. DS00001987A-page 76  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 4.2.18 SPECIAL CONTROL/STATUS INDICATIONS REGISTER Index (In Decimal): 27 Size: 16 bits Bits Description Type Default 15 AMDIXCTRL R/W 0b HP Auto-MDIX control: NASR 0 = Enable Auto-MDIX 1 = Disable Auto-MDIX (use 27.13 to control channel) 14 RESERVED RO - 13 CH_SELECT R/W 0b Manual channel select: NASR 0 = MDI (TX transmits, RX receives) 1 = MDIX (TX receives, RX transmits) 12 RESERVED RO - 11 SQEOFF R/W 0b Disable the SQE test (Heartbeat): NASR 0 = SQE test is enabled 1 = SQE test is disabled 10:5 RESERVED RO - 4 XPOL RO 0b Polarity state of the 10BASE-T: 0 = Normal polarity 1 = Reversed polarity 3:0 RESERVED RO -  2013-2015 Microchip Technology Inc. DS00001987A-page 77

LAN8740A/LAN8740Ai 4.2.19 CABLE LENGTH REGISTER Index (In Decimal): 28 Size: 16 bits Bits Description Type Default 15:12 Cable Length (CBLN) RO 0000b This four bit value indicates the cable length. Refer to Section 3.8.11.2, "Matched Cable Diagnostics" for additional information on the usage of this field. Note: This field indicates cable length for 100BASE-TX linked devices that do not have an open/short on the cable. To determine the open/short status of the cable, the TDR Patterns/Delay Control Register and TDR Control/Status Register must be used. Cable length is not supported for 10BASE-T links. Refer to Section 3.8.11, "Cable Diagnostics" for additional information. 11:0 RESERVED RO - DS00001987A-page 78  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 4.2.20 INTERRUPT SOURCE FLAG REGISTER Index (In Decimal): 29 Size: 16 bits Bits Description Type Default 15:9 RESERVED RO - 8 INT8 RO/LH 0b 0 = Not source of interrupt 1 = Wake on LAN (WoL) event detected 7 INT7 RO/LH 0b 0 = Not source of interrupt 1 = ENERGYON generated 6 INT6 RO/LH 0b 0 = Not source of interrupt 1 = Auto-Negotiation complete 5 INT5 RO/LH 0b 0 = Not source of interrupt 1 = Remote Fault Detected 4 INT4 RO/LH 0b 0 = Not source of interrupt 1 = Link Down (link status negated) 3 INT3 RO/LH 0b 0 = Not source of interrupt 1 = Auto-Negotiation LP Acknowledge 2 INT2 RO/LH 0b 0 = Not source of interrupt 1 = Parallel Detection Fault 1 INT1 RO/LH 0b 0 = Not source of interrupt 1 = Auto-Negotiation Page Received 0 RESERVED RO 0b  2013-2015 Microchip Technology Inc. DS00001987A-page 79

LAN8740A/LAN8740Ai 4.2.21 INTERRUPT MASK REGISTER Index (In Decimal): 30 Size: 16 bits Bits Description Type Default 15:9 RESERVED RO - 8:1 Mask Bits R/W 00000000b These bits mask the corresponding interrupts in the Interrupt Source Flag Register. 0 = Interrupt source is masked. 1 = Interrupt source is enabled. 0 RESERVED RO - DS00001987A-page 80  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 4.2.22 PHY SPECIAL CONTROL/STATUS REGISTER Index (In Decimal): 31 Size: 16 bits Bits Description Type Default 15:13 RESERVED RO - 12 Autodone RO 0b Auto-negotiation done indication: 0 = Auto-negotiation is not done or disabled (or not active). 1 = Auto-negotiation is done. 11:7 RESERVED RO - 6 Enable 4B5B R/W 1b 0 = Bypass encoder/decoder 1 = Enable 4B5B encoding/decoding. MAC interface must be configured in MII mode. 5 RESERVED RO - 4:2 Speed Indication RO XXXb HCDSPEED value: 001 = 10BASE-T half-duplex 101 = 10BASE-T full-duplex 010 = 100BASE-TX half-duplex 110 = 100BASE-TX full-duplex 1:0 RESERVED RO -  2013-2015 Microchip Technology Inc. DS00001987A-page 81

LAN8740A/LAN8740Ai 4.3 MDIO Manageable Device (MMD) Registers The device MMD registers adhere to the IEEE 802.3-2008 45.2 MDIO Interface Registers specification. The MMD reg- isters are not memory mapped. These registers are accessed indirectly via the MMD Access Control Register and MMD Access Address/Data Register. The supported MMD device addresses are 3 (PCS), 7 (Auto-Negotiation), and 30 (Ven- dor Specific). Table4-3, "MMD Registers" details the supported registers within each MMD device. TABLE 4-3: MMD REGISTERS MMD Device Index Address Register Name (In Decimal) (In Decimal) 3 0 PCS Control 1 Register (PCS) 1 PCS Status 1 Register 5 PCS MMD Devices Present 1 Register 6 PCS MMD Devices Present 2 Register 20 EEE Capability Register 22 EEE Wake Error Register 32784 Wakeup Control and Status Register (WUCSR) 32785 Wakeup Filter Configuration Register A (WUF_CFGA) 32786 Wakeup Filter Configuration Register B (WUF_CFGB) 32801 Wakeup Filter Byte Mask Registers (WUF_MASK) 32802 32803 32804 32805 32806 32807 32808 32865 MAC Receive Address A Register (RX_ADDRA) 32866 MAC Receive Address B Register (RX_ADDRB) 32867 MAC Receive Address C Register (RX_ADDRC) 32868 Miscellaneous Configuration Register (MCFGR) 7 5 Auto-Negotiation MMD Devices Present 1 Register (Auto-Negotiation) 6 Auto-Negotiation MMD Devices Present 2 Register 60 EEE Advertisement Register 61 EEE Link Partner Advertisement Register 30 2 Vendor Specific MMD 1 Device ID 1 Register (Vendor Specific) 3 Vendor Specific MMD 1 Device ID 2 Register 5 Vendor Specific 1 MMD Devices Present 1 Register 6 Vendor Specific 1 MMD Devices Present 2 Register 8 Vendor Specific MMD 1 Status Register 11 TDR Match Threshold Register 12 TDR Short/Open Threshold Register 14 Vendor Specific MMD 1 package ID 1 Register 15 Vendor Specific MMD 1 package ID 2 Register DS00001987A-page 82  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai To read or write an MMD register, the following procedure must be observed: 1. Write the MMD Access Control Register with 00b (address) for the MMD Function field and the desired MMD device (3 for PCS, 7 for Auto-Negotiation) for the MMD Device Address (DEVAD) field. 2. Write the MMD Access Address/Data Register with the 16-bit address of the desired MMD register to read/write within the previously selected MMD device (PCS or Auto-Negotiation). 3. Write the MMD Access Control Register with 01b (data) for the MMD Function field and choose the previously selected MMD device (3 for PCS, 7 for Auto-Negotiation) for the MMD Device Address (DEVAD) field. 4. If reading, read the MMD Access Address/Data Register, which contains the selected MMD register contents. If writing, write the MMD Access Address/Data Register with the register contents intended for the previously selected MMD register.  2013-2015 Microchip Technology Inc. DS00001987A-page 83

LAN8740A/LAN8740Ai 4.3.1 PCS CONTROL 1 REGISTER Index (In Decimal): 3.0 Size: 16 bits Bits Description Type Default 15:11 RESERVED RO - 10 Clock Stop Enable R/W 0b 0 = The PHY cannot stop the clock during Low Power Idle (LPI). 1 = The PHY may stop the clock during LPI. Note: The device does not support this mode. 9:0 RESERVED RO - DS00001987A-page 84  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 4.3.2 PCS STATUS 1 REGISTER Index (In Decimal): 3.1 Size: 16 bits Bits Description Type Default 15:12 RESERVED RO - 11 TX LPI Received RO/LH 0b 0 = TX PCS has not received LPI. 1 = TX PCS has received LPI. 10 RX LPI Received RO/LH 0b 0 = RX PCS has not received LPI. 1 = RX PCS has received LPI. 9 TX LPI Indication RO 0b 0 = TX PCS is not currently receiving LPI. 1 = TX PCS is currently receiving LPI. 8 RX LPI Indication RO 0b 0 = RX PCS is not currently receiving LPI. 1 = RX PCS is currently receiving LPI. 7 RESERVED RO - 6 Clock Stop Capable RO 0b 0 = The MAC cannot stop the clock during Low Power Idle (LPI). 1 = The MAC may stop the clock during LPI. Note: The device does not support this mode. 5:0 RESERVED RO -  2013-2015 Microchip Technology Inc. DS00001987A-page 85

LAN8740A/LAN8740Ai 4.3.3 PCS MMD DEVICES PRESENT 1 REGISTER Index (In Decimal): 3.5 Size: 16 bits Bits Description Type Default 15:8 RESERVED RO - 7 Auto-Negotiation Present RO 1b 0 = Auto-negotiation not present in package 1 = Auto-negotiation present in package 6 TC Present RO 0b 0 = TC not present in package 1 = TC present in package 5 DTE XS Present RO 0b 0 = DTE XS not present in package 1 = DTE XS present in package 4 PHY XS Present RO 0b 0 = PHY XS not present in package 1 = PHY XS present in package 3 PCS Present RO 1b 0 = PCS not present in package 1 = PCS present in package 2 WIS Present RO 0b 0 = WIS not present in package 1 = WIS present in package 1 PMD/PMA Present RO 0b 0 = PMD/PMA not present in package 1 = PMD/PMA present in package 0 Clause 22 Registers Present RO 0b 0 = Clause 22 registers not present in package 1 = Clause 22 registers present in package DS00001987A-page 86  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 4.3.4 PCS MMD DEVICES PRESENT 2 REGISTER Index (In Decimal): 3.6 Size: 16 bits Bits Description Type Default 15 Vendor Specific Device 2 Present RO 0b 0 = Vendor specific device 2 not present in package 1 = Vendor specific device 2 present in package 14 Vendor Specific Device 1 Present RO 1b 0 = Vendor specific device 1 not present in package 1 = Vendor specific device 1 present in package 13 Clause 22 Extension Present RO 0b 0 = Clause 22 extension not present in package 1 = Clause 22 extension present in package 12:0 RESERVED RO -  2013-2015 Microchip Technology Inc. DS00001987A-page 87

LAN8740A/LAN8740Ai 4.3.5 EEE CAPABILITY REGISTER Index (In Decimal): 3.20 Size: 16 bits Bits Description Type Default 15:7 RESERVED RO - 6 10GBASE-KR EEE RO 0b 0 = EEE is not supported for 10GBASE-KR. 1 = EEE is supported for 10GBASE-KR. Note: The device does not support this mode. 5 10GBASE-KX4 EEE RO 0b 0 = EEE is not supported for 10GBASE-KX4. 1 = EEE is supported for 10GBASE-KX4. Note: The device does not support this mode. 4 10GBASE-KX EEE RO 0b 0 = EEE is not supported for 10GBASE-KX. 1 = EEE is supported for 10GBASE-KX. Note: The device does not support this mode. 3 10GBASE-T EEE RO 0b 0 = EEE is not supported for 10GBASE-T. 1 = EEE is supported for 10GBASE-T. Note: The device does not support this mode. 2 1000BASE-T EEE RO 0b 0 = EEE is not supported for 1000BASE-T. 1 = EEE is supported for 1000BASE-T. Note: The device does not support this mode. 1 100BASE-TX EEE RO (see Note 1) 0 = EEE is not supported for 100BASE-TX. 1 = EEE is supported for 100BASE-TX. 0 RESERVED RO - Note1: The default value of this field is determined by the value of the PHY Energy Efficient Ethernet Enable (PHY- EEEEN) of the EDPD NLP/Crossover Time/EEE Configuration Register. If PHY Energy Efficient Ethernet Enable (PHYEEEEN) is 0b, this field is 0b and 100BASE-TX EEE capability is not supported. If PHY Energy Efficient Ethernet Enable (PHYEEEEN) is 1b, then this field is 1b and 100BASE-TX EEE capability is sup- ported. DS00001987A-page 88  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 4.3.6 EEE WAKE ERROR REGISTER Index (In Decimal): 3.22 Size: 16 bits Bits Description Type Default 15:0 EEE Wake Error Counter RO/RC 0000h This counter is cleared to zeros on read and is held to all ones on overflow.  2013-2015 Microchip Technology Inc. DS00001987A-page 89

LAN8740A/LAN8740Ai 4.3.7 WAKEUP CONTROL AND STATUS REGISTER (WUCSR) Index (In Decimal): 3.32784 Size: 16 bits Bits Description Type Default 15 Interface Disable R/W 0b 0 = MII/RMII interface enabled NASR 1 = MII/RMII interface disabled. Outputs driven to a low level and inputs ignored. 14:13 LED1 Function Select R/W 0b 00 = LED1 functions as Link/Activity. NASR 01 = LED1 functions as nINT. 10 = LED1 functions as nPME. 11 = LED1 functions as Link Speed. Note: Refer to Section 3.8.1, "LEDs" for additional information. 12:11 LED2 Function Select R/W 0b 00 = LED2 functions as Link Speed. NASR 01 = LED2 functions as nINT. 10 = LED2 functions as nPME. 11 = LED2 functions as Link/Activity. Note: Refer to Section 3.8.1, "LEDs" for additional information. 10 RXD2/RMIISEL Function Select R/W 0b 0 = RXD2/RMIISEL pin functions normally as RXD2/RMIISEL. NASR 1 = RXD2/RMIISEL pin functions as nPME. Note: Refer to Section 3.8.4, "Wake on LAN (WoL)" for additional infor- mation. 9 nPME Self Clear R/W 0b 0 = nPME pin is not self clearing. NASR 1 = nPME pin is self clearing. Note: When set, the de-assertion delay of the nPME signal is controlled by the nPME Assert Delay bit of the Miscellaneous Configuration Register (MCFGR). Refer to Section 3.8.4, "Wake on LAN (WoL)" for additional information. 8 WoL Configured R/W/ 0b This bit may be set by software after the WoL registers are configured. This NASR sticky bit (and all other WoL related register bits) is reset only via a power cycle or a pin reset, allowing software to skip programming of the WoL regis- ters in response to a WoL event. Note: Refer to Section 3.8.4, "Wake on LAN (WoL)" for additional infor- mation. 7 Perfect DA Frame Received (PFDA_FR) R/WC/ 0b The MAC sets this bit upon receiving a valid frame with a destination address NASR that matches the physical address. 6 Remote Wakeup Frame Received (WUFR) R/WC/ 0b The MAC sets this bit upon receiving a valid remote Wakeup Frame. NASR 5 Magic Packet Received (MPR) R/WC/ 0b The MAC sets this bit upon receiving a valid Magic Packet. NASR 4 Broadcast Frame Received (BCAST_FR) R/WC/ 0b The MAC Sets this bit upon receiving a valid broadcast frame. NASR DS00001987A-page 90  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai Bits Description Type Default 3 Perfect DA Wakeup Enable (PFDA_EN) R/W/ 0b When set, remote wakeup mode is enabled and the MAC is capable of waking NASR up on receipt of a frame with a destination address that matches the physical address of the device. The physical address is stored in the MAC Receive Address A Register (RX_ADDRA), MAC Receive Address B Register (RX_ADDRB) and MAC Receive Address C Register (RX_ADDRC). 2 Wakeup Frame Enable (WUEN) R/W/ 0b When set, remote wakeup mode is enabled and the MAC is capable of detect- NASR ing Wakeup Frames as programmed in the Wakeup Filter. 1 Magic Packet Enable (MPEN) R/W/ 0b When set, Magic Packet wakeup mode is enabled. NASR 0 Broadcast Wakeup Enable (BCST_EN) R/W/ 0b When set, remote wakeup mode is enabled and the MAC is capable of waking NASR up from a broadcast frame.  2013-2015 Microchip Technology Inc. DS00001987A-page 91

LAN8740A/LAN8740Ai 4.3.8 WAKEUP FILTER CONFIGURATION REGISTER A (WUF_CFGA) Index (In Decimal): 3.32785 Size: 16 bits Bits Description Type Default 15 Filter Enable R/W/ 0b 0 = Filter disabled NASR 1 = Filter enabled 14 Filter Triggered R/WC/ 0b 0 = Filter not triggered NASR 1 = Filter triggered 13:11 RESERVED RO - 10 Address Match Enable R/W/ 0b When set, the destination address must match the programmed address. NASR When cleared, any unicast packet is accepted. Refer to Section 3.8.4.4, "Wakeup Frame Detection" for additional information. 9 Filter Any Multicast Enable R/W/ 0b When set, any multicast packet other than a broadcast will cause an address NASR match. Refer to Section 3.8.4.4, "Wakeup Frame Detection" for additional information. Note: This bit has priority over bit 10 of this register. 8 Filter Broadcast Enable R/W/ 0b When set, any broadcast frame will cause an address match. Refer to Section NASR 3.8.4.4, "Wakeup Frame Detection" for additional information. Note: This bit has priority over bit 10 of this register. 7:0 Filter Pattern Offset R/W/ 00h Specifies the offset of the first byte in the frame on which CRC checking NASR begins for Wakeup Frame recognition. Offset 0 is the first byte of the incoming frame’s destination address. DS00001987A-page 92  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 4.3.9 WAKEUP FILTER CONFIGURATION REGISTER B (WUF_CFGB) Index (In Decimal): 3.32786 Size: 16 bits Bits Description Type Default 15:0 Filter CRC-16 R/W/ 0000h This field specifies the expected 16-bit CRC value for the filter that should be NASR obtained by using the pattern offset and the byte mask programmed for the fil- ter. This value is compared against the CRC calculated on the incoming frame, and a match indicates the reception of a Wakeup Frame.  2013-2015 Microchip Technology Inc. DS00001987A-page 93

LAN8740A/LAN8740Ai 4.3.10 WAKEUP FILTER BYTE MASK REGISTERS (WUF_MASK) Index (In Decimal): 3.32801 Size: 16 bits Bits Description Type Default 15:0 Wakeup Filter Byte Mask [127:112] R/W/ 0000h NASR Index (In Decimal): 3.32802 Size: 16 bits Bits Description Type Default 15:0 Wakeup Filter Byte Mask [111:96] R/W/ 0000h NASR Index (In Decimal): 3.32803 Size: 16 bits Bits Description Type Default 15:0 Wakeup Filter Byte Mask [95:80] R/W/ 0000h NASR Index (In Decimal): 3.32804 Size: 16 bits Bits Description Type Default 15:0 Wakeup Filter Byte Mask [79:64] R/W/ 0000h NASR Index (In Decimal): 3.32805 Size: 16 bits Bits Description Type Default 15:0 Wakeup Filter Byte Mask [63:48] R/W/ 0000h NASR Index (In Decimal): 3.32806 Size: 16 bits Bits Description Type Default 15:0 Wakeup Filter Byte Mask [47:32] R/W/ 0000h NASR Index (In Decimal): 3.32807 Size: 16 bits DS00001987A-page 94  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai Bits Description Type Default 15:0 Wakeup Filter Byte Mask [31:16] R/W/ 0000h NASR Index (In Decimal): 3.32808 Size: 16 bits Bits Description Type Default 15:0 Wakeup Filter Byte Mask [15:0] R/W/ 0000h NASR  2013-2015 Microchip Technology Inc. DS00001987A-page 95

LAN8740A/LAN8740Ai 4.3.11 MAC RECEIVE ADDRESS A REGISTER (RX_ADDRA) Index (In Decimal): 3.32865 Size: 16 bits Bits Description Type Default 15:0 Physical Address [47:32] R/W/ FFFFh NASR Note: The MAC address must be loaded into the RX_ADDRA, RX_ADDRB, and RX_ADDRC registers in the proper byte order. For example, a MAC address of 12:34:56:78:9A:BC should be loaded into these regis- ters as follows: RX_ADDRA = BC9Ah RX_ADDRB = 7856h RX_ADDRC = 3412h DS00001987A-page 96  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 4.3.12 MAC RECEIVE ADDRESS B REGISTER (RX_ADDRB) Index (In Decimal): 3.32866 Size: 16 bits Bits Description Type Default 15:0 Physical Address [31:16] R/W/ FFFFh NASR Note: The MAC address must be loaded into the RX_ADDRA, RX_ADDRB, and RX_ADDRC registers in the proper byte order. For example, a MAC address of 12:34:56:78:9A:BC should be loaded into these regis- ters as follows: RX_ADDRA = BC9Ah RX_ADDRB = 7856h RX_ADDRC = 3412h  2013-2015 Microchip Technology Inc. DS00001987A-page 97

LAN8740A/LAN8740Ai 4.3.13 MAC RECEIVE ADDRESS C REGISTER (RX_ADDRC) Index (In Decimal): 3.32867 Size: 16 bits Bits Description Type Default 15:0 Physical Address [15:0] R/W/ FFFFh NASR Note: The MAC address must be loaded into the RX_ADDRA, RX_ADDRB, and RX_ADDRC registers in the proper byte order. For example, a MAC address of 12:34:56:78:9A:BC should be loaded into these regis- ters as follows: RX_ADDRA = BC9Ah RX_ADDRB = 7856h RX_ADDRC = 3412h DS00001987A-page 98  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 4.3.14 MISCELLANEOUS CONFIGURATION REGISTER (MCFGR) Index (In Decimal): 3.32868 Size: 16 bits Bits Description Type Default 15:0 nPME Assert Delay R/W/ 1000h This register controls the delay of nPME de-assertion time when the nPME NASR Self Clear bit of the Wakeup Control and Status Register (WUCSR) is set. Each count is equivalent to a 20µs delay. The delay max is 1.31 seconds. Time = (register value + 1) x 20µs.  2013-2015 Microchip Technology Inc. DS00001987A-page 99

LAN8740A/LAN8740Ai 4.3.15 AUTO-NEGOTIATION MMD DEVICES PRESENT 1 REGISTER Index (In Decimal): 7.5 Size: 16 bits Bits Description Type Default 15:8 RESERVED RO - 7 Auto-Negotiation Present RO 1b 0 = Auto-negotiation not present in package 1 = Auto-negotiation present in package 6 TC Present RO 0b 0 = TC not present in package 1 = TC present in package 5 DTE XS Present RO 0b 0 = DTE XS not present in package 1 = DTE XS present in package 4 PHY XS Present RO 0b 0 = PHY XS not present in package 1 = PHY XS present in package 3 PCS Present RO 1b 0 = PCS not present in package 1 = PCS present in package 2 WIS Present RO 0b 0 = WIS not present in package 1 = WIS present in package 1 PMD/PMA Present RO 0b 0 = PMD/PMA not present in package 1 = PMD/PMA present in package 0 Clause 22 Registers Present RO 0b 0 = Clause 22 registers not present in package 1 = Clause 22 registers present in package DS00001987A-page 100  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 4.3.16 AUTO-NEGOTIATION MMD DEVICES PRESENT 2 REGISTER Index (In Decimal): 7.6 Size: 16 bits Bits Description Type Default 15 Vendor Specific Device 2 Present RO 0b 0 = Vendor specific device 2 not present in package 1 = Vendor specific device 2 present in package 14 Vendor Specific Device 1 Present RO 1b 0 = Vendor specific device 1 not present in package 1 = Vendor specific device 1 present in package 13 Clause 22 Extension Present RO 0b 0 = Clause 22 extension not present in package 1 = Clause 22 extension present in package 12:0 RESERVED RO -  2013-2015 Microchip Technology Inc. DS00001987A-page 101

LAN8740A/LAN8740Ai 4.3.17 EEE ADVERTISEMENT REGISTER Index (In Decimal): 7.60 Size: 16 bits Bits Description Type Default 15:2 RESERVED RO - 1 100BASE-TX EEE (see Note 1) (see Note 2) 0 = Do not advertise EEE capability for 100BASE-TX. 1 = Advertise EEE capability for 100BASE-TX. 0 RESERVED RO - Note1: This bit is read/write (R/W). However, the user must not set this bit if EEE is disabled. 2: The default value of this field is determined by the value of the PHY Energy Efficient Ethernet Enable (PHY- EEEEN) of the EDPD NLP/Crossover Time/EEE Configuration Register on page 71. If PHY Energy Efficient Ethernet Enable (PHYEEEEN) is 0b, this field is 0b and 100BASE-TX EEE capability is not advertised. If PHY Energy Efficient Ethernet Enable (PHYEEEEN) is 1b, then this field is 1b and 100BASE-TX EEE capa- bility is advertised. DS00001987A-page 102  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 4.3.18 EEE LINK PARTNER ADVERTISEMENT REGISTER Index (In Decimal): 7.61 Size: 16 bits Bits Description Type Default 15:7 RESERVED RO - 6 10GBASE-KR EEE RO 0b 0 = Link partner does not advertise EEE capability for 10GBASE-KR. 1 = Link partner advertises EEE capability for 10GBASE-KR. Note: This device does not support this mode. 5 10GBASE-KX4 EEE RO 0b 0 = Link partner does not advertise EEE capability for 10GBASE-KX4. 1 = Link partner advertises EEE capability for 10GBASE-KX4. Note: This device does not support this mode. 4 10GBASE-KX EEE RO 0b 0 = Link partner does not advertise EEE capability for 10GBASE-KX. 1 = Link partner advertises EEE capability for 10GBASE-KX. Note: This device does not support this mode. 3 10GBASE-T EEE RO 0b 0 = Link partner does not advertise EEE capability for 10GBASE-T. 1 = Link partner advertises EEE capability for 10GBASE-T. Note: This device does not support this mode. 2 1000BASE-T EEE RO 0b 0 = Link partner does not advertise EEE capability for 1000BASE-T. 1 = Link partner advertises EEE capability for 1000BASE-T. Note: This device does not support this mode. 1 100BASE-TX EEE RO 0b 0 = Link partner does not advertise EEE capability for 100BASE-TX. 1 = Link partner advertises EEE capability for 100BASE-TX. 0 RESERVED RO -  2013-2015 Microchip Technology Inc. DS00001987A-page 103

LAN8740A/LAN8740Ai 4.3.19 VENDOR SPECIFIC MMD 1 DEVICE ID 1 REGISTER Index (In Decimal): 30.2 Size: 16 bits Bits Description Type Default 15:0 RESERVED RO 0000h DS00001987A-page 104  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 4.3.20 VENDOR SPECIFIC MMD 1 DEVICE ID 2 REGISTER Index (In Decimal): 30.3 Size: 16 bits Bits Description Type Default 15:0 RESERVED RO 0000h  2013-2015 Microchip Technology Inc. DS00001987A-page 105

LAN8740A/LAN8740Ai 4.3.21 VENDOR SPECIFIC 1 MMD DEVICES PRESENT 1 REGISTER Index (In Decimal): 30.5 Size: 16 bits Bits Description Type Default 15:8 RESERVED RO - 7 Auto-Negotiation Present RO 1b 0 = Auto-negotiation not present in package 1 = Auto-negotiation present in package 6 TC Present RO 0b 0 = TC not present in package 1 = TC present in package 5 DTE XS Present RO 0b 0 = DTE XS not present in package 1 = DTE XS present in package 4 PHY XS Present RO 0b 0 = PHY XS not present in package 1 = PHY XS present in package 3 PCS Present RO 1b 0 = PCS not present in package 1 = PCS present in package 2 WIS Present RO 0b 0 = WIS not present in package 1 = WIS present in package 1 PMD/PMA Present RO 0b 0 = PMD/PMA not present in package 1 = PMD/PMA present in package 0 Clause 22 Registers Present RO 0b 0 = Clause 22 registers not present in package 1 = Clause 22 registers present in package DS00001987A-page 106  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 4.3.22 VENDOR SPECIFIC 1 MMD DEVICES PRESENT 2 REGISTER Index (In Decimal): 30.6 Size: 16 bits Bits Description Type Default 15 Vendor Specific Device 2 Present RO 0b 0 = Vendor specific device 2 not present in package 1 = Vendor specific device 2 present in package 14 Vendor Specific Device 1 Present RO 1b 0 = Vendor specific device 1 not present in package 1 = Vendor specific device 1 present in package 13 Clause 22 Extension Present RO 0b 0 = Clause 22 extension not present in package 1 = Clause 22 extension present in package 12:0 RESERVED RO -  2013-2015 Microchip Technology Inc. DS00001987A-page 107

LAN8740A/LAN8740Ai 4.3.23 VENDOR SPECIFIC MMD 1 STATUS REGISTER Index (In Decimal): 30.8 Size: 16 bits Bits Description Type Default 15:14 Device Present 10b 00 = No device responding at this address 01 = No device responding at this address 10 = Device responding at this address 11 = No device responding at this address 13:0 RESERVED RO - DS00001987A-page 108  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 4.3.24 TDR MATCH THRESHOLD REGISTER Index (In Decimal): 30.11 Size: 16 bits Bits Description Type Default 15:10 RESERVED RO - 9:5 TDR Match High Threshold R/W 5’h12 Sets the upper threshold to detect match cable. (see Note 1) 4:0 TDR Match Low Threshold R/W 5’h09 Sets the lower threshold to detect match cable. (see Note 1) Note1: Software reset places the default values of this register into an indeterminate state. For proper operation of the TDR, the TDR Match High Threshold and TDR Match Low Threshold must be set to 5’h12 and 5’h09, respectively.  2013-2015 Microchip Technology Inc. DS00001987A-page 109

LAN8740A/LAN8740Ai 4.3.25 TDR SHORT/OPEN THRESHOLD REGISTER Index (In Decimal): 30.12 Size: 16 bits Bits Description Type Default 15:10 RESERVED RO - 9:5 TDR Short Low Threshold R/W 5’h09 Sets the lower threshold to detect short cable. (see Note 1) 4:0 TDR Open High Threshold R/W 5’h12 Sets the upper threshold to detect open cable. (see Note 1) Note1: Software reset places the default values of this register into an indeterminate state. For proper operation of the TDR, the TDR Short Low Threshold and TDR Open High Threshold must be set to 5’h09 and 5’h12, respectively. DS00001987A-page 110  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 4.3.26 VENDOR SPECIFIC MMD 1 PACKAGE ID 1 REGISTER Index (In Decimal): 30.14 Size: 16 bits Bits Description Type Default 15:0 RESERVED RO 0000h  2013-2015 Microchip Technology Inc. DS00001987A-page 111

LAN8740A/LAN8740Ai 4.3.27 VENDOR SPECIFIC MMD 1 PACKAGE ID 2 REGISTER Index (In Decimal): 30.15 Size: 16 bits Bits Description Type Default 15:0 RESERVED RO 0000h DS00001987A-page 112  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 5.0 OPERATIONAL CHARACTERISTICS 5.1 Absolute Maximum Ratings* Supply Voltage (VDDIO, VDD1A, VDD2A) (see Note 1)..........................................................................-0.5 V to +3.6 V Digital Core Supply Voltage (VDDCR) (see Note 1)................................................................................-0.5 V to +1.5 V Ethernet Magnetics Supply Voltage.........................................................................................................-0.5 V to +3.6 V Positive voltage on input signal pins, with respect to ground (see Note 2)...............................................VDDIO + 2.0 V Negative voltage on input signal pins, with respect to ground (see Note 3)............................................................-0.5 V Positive voltage on XTAL1/CLKIN, with respect to ground.......................................................................................3.6V Storage Temperature..............................................................................................................................-55oC to +150oC Lead Temperature Range...........................................................................................Refer to JEDEC Spec. J-STD-020 HBM ESD Performance.........................................................................................................................JEDEC Class 3A Note1: When powering this device from laboratory or system power supplies, it is important that the absolute max- imum ratings not be exceeded or device failure can result. Some power supplies exhibit voltage spikes on their outputs when AC power is switched on or off. In addition, voltage transients on the AC power line may appear on the DC output. If this possibility exists, it is suggested that a clamp circuit be used. 2: This rating does not apply to the following pins: XTAL1/CLKIN, XTAL2, RBIAS. 3: This rating does not apply to the following pins: RBIAS. *Stresses exceeding those listed in this section could cause permanent damage to the device. This is a stress rating only. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Functional operation of the device at any condition exceeding those indicated in Section 5.2, "Operating Conditions**" or any other applicable section of this specification is not implied. Note, device signals are NOT 5.0 V tolerant unless specified oth- erwise. 5.2 Operating Conditions** Supply Voltage (VDDIO).......................................................................................................................+1.62 V to +3.6 V Analog Port Supply Voltage (VDD1A, VDD2A).......................................................................................+3.0 V to +3.6 V Digital Core Supply Voltage (VDDCR)................................................................................................+1.14 V to +1.26 V Ethernet Magnetics Supply Voltage......................................................................................................+2.25 V to +3.6 V Ambient Operating Temperature in Still Air (T )........................................................................................... (see Note 1) A Note1: 0°C to +70°C for commercial version, -40°C to +85°C for industrial version. **Proper operation of the device is guaranteed only within the ranges specified in this section. After the device has com- pleted power-up, VDDIO and the magnetics power supply must maintain their voltage level with ±10%. Varying the volt- age greater than ±10% after the device has completed power-up can cause errors in device operation. Note: Do not drive input signals without power supplied to the device. 5.3 Package Thermal Specifications TABLE 5-1: PACKAGE THERMAL PARAMETERS Parameter Symbol Value Unit Comment Thermal Resistance Θ 47.8 oC/W Measured in still air from the die to ambient air JA Junction-to-Top-of-Package Ψ 0.7 oC/W Measured in still air JT Note: Thermal parameters are measured or estimated for devices in a multi-layer 2S2P PCB per JESD51.  2013-2015 Microchip Technology Inc. DS00001987A-page 113

LAN8740A/LAN8740Ai 5.4 Power Consumption This section details the device power measurements taken over various operating conditions. Unless otherwise noted, all measurements were taken with power supplies at nominal values (VDDIO, VDD1A, VDD2A = 3.3V, VDDCR = 1.2V). See Section 3.8.3, "Power-Down Modes" for a description of the power down modes. 5.4.1 REGULATOR DISABLED TABLE 5-2: CURRENT CONSUMPTION AND POWER DISSIPATION (REG. DISABLED) 3.3V Device 3.3V Device 1.2V Device Current w/ Total Device Power Pin Group Current (mA) Current (mA) Magnetics Power (mW) (mA) nRESET Typical 9.7 11 9.7 45 100BASE-TX /W TRAFFIC Typical 32 21 74 130 (NO EEE) 10BASE-T /W TRAFFIC Typical 11 13 114 51 100BASE-TX IDLE /W EEE Typical 32 15 32 122 ENERGY DETECT Typical 4.0 1.7 4.0 15 POWER DOWN GENERAL POWER DOWN Typical 0.3 1.4 0.4 2.8 5.4.2 REGULATOR ENABLED TABLE 5-3: CURRENT CONSUMPTION AND POWER DISSIPATION (REG. ENABLED) Device Current w/ Total Device Power Power Pin Group Device Current (mA) Magnetics (mA) (mW) nRESET Typical 21 21 70 100BASE-TX /W TRAFFIC Typical 55 97 180 (NO EEE) 10BASE-T /W TRAFFIC Typical 25 129 82 100BASE-TX IDLE /W EEE Typical 48 48 158 ENERGY DETECT Typical 7.1 7.1 24 POWER DOWN GENERAL POWER DOWN Typical 4.0 4.0 13 DS00001987A-page 114  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 5.5 DC Specifications Table 5-4 details the non-variable I/O buffer characteristics. These buffer types do not support variable voltage opera- tion. Table 5-5 details the variable voltage I/O buffer characteristics. Typical values are provided for 1.8 V, 2.5 V, and 3.3 V VDDIO cases. TABLE 5-4: NON-VARIABLE I/O BUFFER CHARACTERISTICS Parameter Symbol Min. Typ. Max. Unit Note IS Type Input Buffer Low Input Level V -0.3 V ILI High Input Level V 3.6 V IHI Negative-Going Threshold V 1.01 1.19 1.39 V Schmitt trigger ILT Positive-Going Threshold V 1.39 1.59 1.79 V Schmitt trigger IHT Schmitt Trigger Hysteresis V 336 399 459 mV HYS (V - V ) IHT ILT Input Leakage I -10 10 µA (see Note 1) IH (V = VSS or VDDIO) IN Input Capacitance C 2 pF IN O12 Type Buffers Low Output Level V 0.4 V I = 12 mA OL OL High Output Level V VDD2A - 0.4 V I = -12 mA OH OH ICLK Type Buffer (see Note 2) (XTAL1 Input) Low Input Level V -0.3 0.35 V ILI High Input Level VIHI VDDCR-0.35 3.6 V Note1: This specification applies to all inputs and tri-stated bi-directional pins. Internal pull-down and pull-up resis- tors add ±50 µA per-pin (typical). 2: XTAL1/CLKIN can optionally be driven from a 25 MHz single-ended clock oscillator.  2013-2015 Microchip Technology Inc. DS00001987A-page 115

LAN8740A/LAN8740Ai TABLE 5-5: VARIABLE I/O BUFFER CHARACTERISTICS 1.8 V 2.5 V 3.3 V Parameter Symbol Min. Max. Unit Note Typ. Typ. Typ. VIS Type Input Buffer Low Input Level V -0.3 V ILI High Input Level V 3.6 V IHI Neg-Going Threshold V 0.64 0.83 1.15 1.41 1.76 V Schmitt trigger ILT Pos-Going Threshold V 0.81 0.99 1.29 1.65 1.90 V Schmitt trigger IHT Schmitt Trigger Hystere- V 102 158 136 138 288 mV HYS sis (V - V ) IHT ILT Input Leakage I -10 10 µA (see Note 1) IH (V = VSS or VDDIO) IN Input Capacitance C 2 pF IN VO8 Type Buffers Low Output Level V 0.4 V I = 8 mA OL OL High Output Level V VDDIO - 0.4 V I = -8 mA OH OH VOD8 Type Buffer Low Output Level V 0.4 V I = 8 mA OL OL Note1: This specification applies to all inputs and tri-stated bi-directional pins. Internal pull-down and pull-up resis- tors add ±50 µA per-pin (typical). TABLE 5-6: 100BASE-TX TRANSCEIVER CHARACTERISTICS Parameter Symbol Min. Typ. Max. Unit Note Peak Differential Output Voltage High V 950 - 1050 mVpk (see Note 1) PPH Peak Differential Output Voltage Low V -950 - -1050 mVpk (see Note 1) PPL Signal Amplitude Symmetry V 98 - 102 % (see Note 1) SS Signal Rise and Fall Time T 3.0 - 5.0 ns (see Note 1) RF Rise and Fall Symmetry T - - 0.5 ns (see Note 1) RFS Duty Cycle Distortion D 35 50 65 % (see Note 2) CD Overshoot and Undershoot V - - 5 % OS Jitter 1.4 ns (see Note 3) Note1: Measured at line side of transformer, line replaced by 100 Ω (±1%) resistor. 2: Offset from 16 ns pulse width at 50% of pulse peak. 3: Measured differentially. TABLE 5-7: 10BASE-T TRANSCEIVER CHARACTERISTICS Parameter Symbol Min. Typ. Max. Unit Note Transmitter Peak Differential Output Voltage V 2.2 2.5 2.8 V (see Note 1) OUT Receiver Differential Squelch Threshold V 300 420 585 mV DS Note1: Min/max voltages guaranteed as measured with 100 Ω resistive load. DS00001987A-page 116  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 5.6 AC Specifications This section details the various AC timing specifications of the device. 5.6.1 EQUIVALENT TEST LOAD Output timing specifications assume a 25 pF equivalent test load, unless otherwise noted, as illustrated in Figure 5-1 below. FIGURE 5-1: OUTPUT EQUIVALENT TEST LOAD OUTPUT 25 pF  2013-2015 Microchip Technology Inc. DS00001987A-page 117

LAN8740A/LAN8740Ai 5.6.2 POWER-ON nRST & CONFIGURATION STRAP TIMING This diagram illustrates the nRST reset and configuration strap timing requirements in relation to power-on. A hardware reset (nRST assertion) is required following power-up. For proper operation, nRST must be asserted for no less than t The nRST pin can be asserted at any time, but must not be deasserted before t after all external power sup- rstia. purstd plies have reached operational levels. In order for valid configuration strap values to be read at power-up, the t and css t timing constraints must be followed. Refer to Section 3.8.7, "Resets" for additional information. csh FIGURE 5-2: POWER-ON nRST & CONFIGURATION STRAP TIMING All External Vopp Power Supplies t purstd t t purstv rstia nRST t t css csh Configuration Strap Pins Input t t otaa odad Configuration Strap Pins Output Drive TABLE 5-8: POWER-ON nRST & CONFIGURATION STRAP TIMING VALUES Symbol Description Min. Typ. Max. Unit t External power supplies at operational level to nRST 25 ms purstd deassertion t External power supplies at operational level to nRST 0 ns purstv valid t nRST input assertion time 100 µs rstia t Configuration strap pins setup to nRST deassertion 200 ns css t Configuration strap pins hold after nRST deassertion 1 ns csh t Output tri-state after nRST assertion 50 ns otaa t Output drive after nRST deassertion 2 800 ns odad (see Note 1) Note: nRST deassertion must be monotonic. Note: Device configuration straps are latched as a result of nRST assertion. Refer to Section 3.7, "Configuration Straps" for details. Configuration straps must only be pulled high or low and must not be driven as inputs. Note1: 20 clock cycles for 25 MHz, or 40 clock cycles for 50 MHz DS00001987A-page 118  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 5.6.3 MII INTERFACE TIMING This section specifies the MII interface transmit and receive timing. Please refer to Section 3.4.1, "MII" for additional details. FIGURE 5-3: MII RECEIVE TIMING t clkp t t clkh clkl RXCLK (OUTPUT) t t t val val invld RXD[3:0] (OUTPUTS) t invld t val RXDV, RXER (OUTPUTS) TABLE 5-9: MII RECEIVE TIMING VALUES Symbol Description Min. Typ. Max. Unit Note t RXCLK period (see Note 1) ns clkp t RXCLK high time t * 0.4 t * 0.6 ns clkh clkp clkp t RXCLK low time t * 0.4 t * 0.6 ns clkl clkp clkp t RXD[3:0], RXDV, RXER output 28.0 ns (see Note 2) val valid from rising edge of RXCLK t RXD[3:0], RXDV, RXER output 10.0 ns (see Note 2) invld invalid from rising edge of RXCLK Note1: 40 ns for 100BASE-TX operation, 400 ns for 10BASE-T operation. 2: Timing was designed for system load between 10 pF and 25 pF.  2013-2015 Microchip Technology Inc. DS00001987A-page 119

LAN8740A/LAN8740Ai FIGURE 5-4: MII TRANSMIT TIMING t clkp t t clkh clkl TXCLK (OUTPUT) t t t t t su hold su hold hold TXD[3:0] (INPUTS) t t hold su TXEN, TXER (INPUTS) TABLE 5-10: MII TRANSMIT TIMING VALUES Symbol Description Min. Typ. Max. Unit Note t TXCLK period (see Note 1) ns clkp t TXCLK high time t * 0.4 t * 0.6 ns clkh clkp clkp t TXCLK low time t * 0.4 t * 0.6 ns clkl clkp clkp t TXD[3:0], TXEN, TXER setup time 12.0 ns (see Note 2) su to rising edge of TXCLK t TXD[3:0], TXEN, TXER hold time 0 ns (see Note 2) hold after rising edge of TXCLK t TXCLK rising edge after TXEN 160 162 ns (see Note 2) 1 assertion to RXDV assertion (100Mbps internal loopback mode) Note1: 40 ns for 100BASE-TX operation, 400 ns for 10BASE-T operation. 2: Timing was designed for system load between 10 pF and 25 pF. DS00001987A-page 120  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 5.6.3.1 100Mbps Internal Loopback MII Timing FIGURE 5-5: 100 MBPS INTERNAL LOOPBACK MII TIMING TXCLK (OUTPUT) TXEN (INPUT) t 1 RXDV (OUTPUT) RXD[3:0] (OUTPUTS) TABLE 5-11: 100 MBPS INTERNAL LOOPBACK MII TIMING VALUES Symbol Description Min. Typ. Max. Unit t TXCLK rising edge after TXEN assertion to 160 161 162 ns 1 RXDV assertion (100Mbps internal loopback MII mode) Note: The t measurement applies in MII mode when the Loopback bit of the Basic Control Register is set to “1” 1 and a link has been established in 100Mb full-duplex mode. The t measurement is taken from the first 1 rising edge of TXCLK following assertion of TXEN to the rising edge of RXDV.  2013-2015 Microchip Technology Inc. DS00001987A-page 121

LAN8740A/LAN8740Ai 5.6.4 RMII INTERFACE TIMING This section specifies the RMII interface transmit and receive timing. Note: The CRS_DV pin performs both carrier sense and data valid functions. CRS_DV is asserted asynchro- nously on detection of carrier due to the criteria relevant to the operating mode. If the PHY has additional bits to be presented on RXD[1:0] following the initial deassertion of CRS_DV, then the device will assert CRS_DV on cycles of REF_CLK which present the second di-bit of each nibble and deassert CRS_DV on cycles of REF_CLK which present the first di-bit of a nibble. For additional information, refer to the RMII specification. FIGURE 5-6: RMII TIMING t clkp t t CLKIN clkh clkl (REF_CLK) (INPUT) t t t oval oval oinvld RXD[1:0], RXER (OUTPUTS) toinvld toval CRS_DV (OUTPUT) t t t t t su ihold su ihold ihold TXD[1:0] (INPUTS) t t ihold su TXEN (INPUT) TABLE 5-12: RMII TIMING VALUES Symbol Description Min. Typ. Max. Unit Note t CLKIN period 20 ns clkp t CLKIN high time t * 0.35 t * 0.65 ns clkh clkp clkp t CLKIN low time t * 0.35 t * 0.65 ns clkl clkp clkp t RXD[1:0], RXER, CRS_DV output 15.0 ns (see Note 1) oval valid from rising edge of CLKIN t RXD[1:0], RXER, CRS_DV output 3.0 ns (see Note 1) oinvld invalid from rising edge of CLKIN t TXD[1:0], TXEN setup time to ris- 4.0 ns (see Note 1) su ing edge of CLKIN t TXD[1:0], TXEN input hold time 1.5 ns (see Note 1) ihold after rising edge of CLKIN Note1: Timing was designed for system load between 10 pF and 25 pF. DS00001987A-page 122  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 5.6.4.1 RMII CLKIN Requirements TABLE 5-13: RMII CLKIN (REF_CLK) TIMING VALUES Parameter Min. Typ. Max. Unit Note CLKIN frequency 50 MHz CLKIN Frequency Drift ±50 ppm CLKIN Duty Cycle 40 60 % CLKIN Jitter 150 ps p-p – not RMS 5.6.5 SMI TIMING This section specifies the SMI timing of the device. Please refer to Section 3.5, "Serial Management Interface (SMI)" for additional details. FIGURE 5-7: SMI TIMING t clkp t t clkh clkl MDC (INPUT) t t val oinvld t oinvld MDIO (Data-Out) t t su ihold MDIO (Data-In) TABLE 5-14: SMI TIMING VALUES Symbol Description Min. Max. Unit t MDC period 400 ns clkp t MDC high time 160 (80%) ns clkh t MDC low time 160 (80%) ns clkl t MDIO (read from PHY) output valid from rising edge of MDC 300 ns val t MDIO (read from PHY) output invalid from rising edge of MDC 0 ns oinvld t MDIO (write to PHY) setup time to rising edge of MDC 10 ns su t MDIO (write to PHY) input hold time after rising edge of MDC 10 ns ihold  2013-2015 Microchip Technology Inc. DS00001987A-page 123

LAN8740A/LAN8740Ai 5.7 Clock Circuit The device can accept either a 25MHz crystal or a 25MHz single-ended clock oscillator (±50ppm) input. If the single- ended clock oscillator method is implemented, XTAL2 should be left unconnected and XTAL1/CLKIN should be driven with a nominal 0-3.3V clock signal. The input clock duty cycle is 40% minimum, 50% typical and 60% maximum. It is recommended that a crystal utilizing matching parallel load capacitors be used for the crystal input/output signals (XTAL1/XTAL2). Either a 300µW or 100µW 25MHz crystal may be utilized. The 300µW 25MHz crystal specifications are detailed in Section 5.7.1, "300µW 25MHz Crystal Specifications". The 100µW 25MHz crystal specifications are detailed in Section 5.7.2, "100µW 25MHz Crystal Specifications". 5.7.1 300µW 25MHZ CRYSTAL SPECIFICATIONS When utilizing a 300µW 25MHz crystal, the following circuit design (Figure 5-8) and specifications (Table 5-15) are required to ensure proper operation. FIGURE 5-8: 300µW 25MHZ CRYSTAL CIRCUIT LAN8740 XTAL2 Y1 XTAL1 C C 1 2 TABLE 5-15: 300µW CRYSTAL SPECIFICATIONS Parameter Symbol Min. Nom. Max. Unit Note Crystal Cut AT, typ Crystal Oscillation Mode Fundamental Mode Crystal Calibration Mode Parallel Resonant Mode Frequency F - 25.000 - MHz fund Frequency Tolerance at 25oC F - - ±50 ppm (see Note 1) tol Frequency Stability Over Temp F - - ±50 ppm (see Note 1) temp Frequency Deviation Over Time F - ±3 to 5 - ppm (see Note 2) age Total Allowable PPM Budget - - ±50 ppm (see Note 3) Shunt Capacitance C - 7 typ - pF O Load Capacitance C - 20 typ - pF L Drive Level P 300 - - µW W Equivalent Series Resistance R - - 50 Ω 1 Operating Temperature Range (see Note 4) - (see Note 5) oC XTAL1/CLKIN Pin Capacitance - 3 typ - pF (see Note 6) XTAL2 Pin Capacitance - 3 typ - pF (see Note 6) Note1: The maximum allowable values for frequency tolerance and frequency stability are application dependent. Since any particular application must meet the IEEE ±50 ppm Total PPM Budget, the combination of these two values must be approximately ±45 ppm (allowing for aging). 2: Frequency Deviation Over Time is also referred to as Aging. DS00001987A-page 124  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 3: The total deviation for the Transmitter Clock Frequency is specified by IEEE 802.3u as ±50 ppm. 4: 0°C for commercial version, -40°C for industrial version 5: +70°C for commercial version, +85°C for industrial version 6: This number includes the pad, the bond wire and the lead frame. PCB capacitance is not included in this value. The XTAL1/CLKIN pin, XTAL2 pin and PCB capacitance values are required to accurately calculate the value of the two external load capacitors. These two external load capacitors determine the accuracy of the 25.000 MHz frequency. 5.7.2 100µW 25MHZ CRYSTAL SPECIFICATIONS When utilizing a 100µW 25MHz crystal, the following circuit design (Figure 5-9) and specifications (Table 5-16) are required to ensure proper operation. FIGURE 5-9: 100µW 25MHZ CRYSTAL CIRCUIT LAN8740 XTAL2 R S Y1 XTAL1 C C 1 2 TABLE 5-16: 100µW CRYSTAL SPECIFICATIONS Parameter Symbol Min. Nom. Max. Unit Note Crystal Cut AT, typ Crystal Oscillation Mode Fundamental Mode Crystal Calibration Mode Parallel Resonant Mode Frequency F - 25.000 - MHz fund Frequency Tolerance at 25oC F - - ±50 ppm (see Note 1) tol Frequency Stability Over Temp F - - ±50 ppm (see Note 1) temp Frequency Deviation Over Time F - ±3 to 5 - ppm (see Note 2) age Total Allowable PPM Budget - - ±50 ppm (see Note 3) Shunt Capacitance C - - 5 pF O Load Capacitance C 8 - 12 pF L Drive Level P - 100 - µW (see Note 4) W Equivalent Series Resistance R - - 80 Ω 1 XTAL2 Series Resistor R 495 500 505 Ohm S Operating Temperature Range (see Note 5) - (see Note 6) oC XTAL1/CLKIN Pin Capacitance - 3 typ - pF (see Note 7) XTAL2 Pin Capacitance - 3 typ - pF (see Note 7)  2013-2015 Microchip Technology Inc. DS00001987A-page 125

LAN8740A/LAN8740Ai Note1: The maximum allowable values for frequency tolerance and frequency stability are application dependent. Since any particular application must meet the IEEE ±50 ppm Total PPM Budget, the combination of these two values must be approximately ±45 ppm (allowing for aging). 2: Frequency Deviation Over Time is also referred to as Aging. 3: The total deviation for the Transmitter Clock Frequency is specified by IEEE 802.3u as ±50 ppm. 4: The crystal must support 100µW operation to utilize this circuit. 5: 0°C for commercial version, -40°C for industrial version 6: +70°C for commercial version, +85°C for industrial version 7: This number includes the pad, the bond wire and the lead frame. PCB capacitance is not included in this value. The XTAL1/CLKIN pin, XTAL2 pin and PCB capacitance values are required to accurately calculate the value of the two external load capacitors (C and C in Figure 5-9). The external load capacitors, C and 1 2 1 C , determine the accuracy of the 25.000 MHz frequency. 2 DS00001987A-page 126  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 6.0 PACKAGE OUTLINE 32-Lead Very Thin Plastic Quad Flat, No Lead Package (MQ) - 5x5x0.9 mm Body [VQFN] SMSC LEGACY SQFN Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging D A B N 1 2 NOTE 1 E (DATUM B) (DATUM A) 2X 0.20 C 2X 0.20 C TOP VIEW (A3) 0.10 C A1 C A SEATING PLANE 32X SIDE VIEW 0.08 C 0.10 C A B D2 0.10 C A B E2 e 2 2 1 NOTE 1 N 32X K 32X L 32X b e 0.10 C A B 0.05 C BOTTOM VIEW Microchip Technology Drawing C04-160B SQFN Sheet 1 of 2  2013-2015 Microchip Technology Inc. DS00001987A-page 127

LAN8740A/LAN8740Ai 32-Lead Very Thin Plastic Quad Flat, No Lead Package (MQ) - 5x5x0.9 mm Body [VQFN] SMSC LEGACY SQFN Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging Units MILLIMETERS Dimension Limits MIN NOM MAX Number of Terminals N 32 Pitch e 0.50 BSC Overall Height A 0.80 0.90 1.00 Standoff A1 0.00 0.02 0.05 Terminal Thickness A3 0.20 REF Overall Width E 5.00 BSC Exposed Pad Width E2 3.20 3.30 3.40 Overall Length D 5.00 BSC Exposed Pad Length D2 3.20 3.30 3.40 Terminal Width b 0.18 0.25 0.30 Terminal Length L 0.35 0.40 0.45 Terminal-to-Exposed-Pad K 0.20 - - Notes: 1. Pin 1 visual index feature may vary, but must be located within the hatched area. 2. Package is saw singulated 3. Dimensioning and tolerancing per ASME Y14.5M BSC: Basic Dimension. Theoretically exact value shown without tolerances. REF: Reference Dimension, usually without tolerance, for information purposes only. Microchip Technology Drawing C04-160B SQFN Sheet 2 of 2 DS00001987A-page 128  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai 32-Lead Very Thin Plastic Quad Flat, No Lead Package (MQ) - 5x5mm Body [VQFN] SMSC LEGACY SQFN Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging C1 X2 EV 32 1 ØV 2 G2 C2 Y2 EV G1 Y1 X1 E SILK SCREEN RECOMMENDED LAND PATTERN Units MILLIMETERS Dimension Limits MIN NOM MAX Contact Pitch E 0.50 BSC Optional Center Pad Width X2 3.40 Optional Center Pad Length Y2 3.40 Contact Pad Spacing C1 4.90 Contact Pad Spacing C2 4.90 Contact Pad Width (X32) X1 0.30 Contact Pad Length (X32) Y1 0.85 Contact Pad to Center Pad (X32) G1 0.33 Contact Pad to Contactr Pad (X28) G2 0.20 Thermal Via Diameter V 0.33 Thermal Via Pitch EV 1.20 Notes: 1. Dimensioning and tolerancing per ASME Y14.5M BSC: Basic Dimension. Theoretically exact value shown without tolerances. 2. For best soldering results, thermal vias, if used, should be filled or tented to avoid solder loss during reflow process Microchip Technology Drawing C04-2160C SQFN  2013-2015 Microchip Technology Inc. DS00001987A-page 129

LAN8740A/LAN8740Ai APPENDIX A: REVISION HISTORY REVISION LEVEL & DATE SECTION/FIGURE/ENTRY CORRECTION Revision A Replaces the previous SMSC version Rev. 1.1 (09-07-15) • Added Note and Trademark page • Added Worldwide Sales and Services page • Added Product Identification System • Changed ‘QFN’ to ‘VQFN’ Chapter 2, "Pin Description and • Figure2-1: rotated 90° cw Configuration" • Table2-3, “Serial Management Interface (SMI) Pins”: Changed “VIS/VOD8 (PU)” to “VIS/VO8 (PU)” Section 4.1, "Register Nomenclature" Table4-1, “Register Bit Types”, register bit description for byte type notification ‘W’: Changed “read” to ‘written” Section 5.6.4, "RMII Interface Timing" Updated RMII timing table: Updated REF_CLK In mode t max from “14.0ns” to “15.0ns” oval Section 5.7, "Clock Circuit" Added new 100µW crystal specifications and circuit diagram. The section is now split into two subsections, one for 300µW crystals and the other for 100µW crystals. Chapter 6, "Package Outline" Updated package outline drawing information Rev. 1.1 General • Changed part numbers from (05-10-13) “LAN8740/LAN8740i” to “LAN8740A/LAN8740Ai” • Updated ordering information • Updated figures Cover Added new bullet under Highlights section: “Deterministic 100Mb internal loopback latency (MII Mode)” Chapter 2, "Pin Description and Changed buffer type from “VIS (PU)” to “VIS” Configuration", Table2-1, “MII/RMII Signals” Chapter 2, "Pin Description and • Added pull-up to MDIO buffer type description Configuration", Table2-3, “Serial • Changed “VIS/VOD8 (PU)” to “VIS/VO8 (PU)” Management Interface (SMI) Pins” Section 3.3, "HP Auto-MDIX Support" Changed “100BASE-T” to “100BASE-TX” Section 3.4.2.1, "CRS_DV - Carrier Changed “100BASE-X” to “100BASE-TX” Sense/Receive Data Valid" Section 3.5, "Serial Management Removed sentence stating “Non-supported registers Interface (SMI)" (such as 7 to 15) will be read as hexadecimal “FFFF”. Section 3.8.11, "Cable Diagnostics" Updated section with additional operation details Section 3.8.12.1, "Near-end Loopback" Added cross-reference to 100Mbps internal loopback timing section , "," on page58 Removed - TDR Channel Threshold Maximum Register - TDR Wait Counter Threshold Register - TDR TX Pattern Generator Divider Register Section 4.2.2, "Basic Status Register" Updated definitions of bits 10:8 Section 4.2.18, "Special Control/Status Updated bit 11 definition Indications Register" Section 4.2.22, "PHY Special Updated bit 6 definition Control/Status Register" DS00001987A-page 130  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai REVISION LEVEL & DATE SECTION/FIGURE/ENTRY CORRECTION Rev. 1.1 Section 4.3, "MDIO Manageable Device Added additional vendor specific MMD register (05-10-13) (MMD) Registers" descriptions Section 4.3.11, "MAC Receive Address Added note A Register (RX_ADDRA)" Section 4.3.12, "MAC Receive Address Added note B Register (RX_ADDRB)" Section 4.3.13, "MAC Receive Address Added note C Register (RX_ADDRC)" , "," on page113 Removed section “Power Sequence Timing” Section 5.1, "Absolute Maximum Changed: Positive voltage on XTAL1/CLKIN, with Ratings*" respect to ground from “VDDCR” to “+3.6V” Section5.3, Table5-1, “Package Updated package thermal specification values Thermal Parameters” Section 5.4, "Power Consumption" Updated power numbers Section 5.5, "DC Specifications" Changed V max of ICLK Type Buffer from IHI “VDDCR” to “3.6” Section 5.6, "AC Specifications" Removed two RMII notes at beginning of section Section 5.6.3.1, "100Mbps Internal Added new 100Mbps internal loopback timing Loopback MII Timing" section and diagram Section 5.6.4, "RMII Interface Timing" Added note detailing CRS_DV behavior as both carrier sense and data valid Updated RMII timing table Rev. 1.0 Initial Release (05-11-12)  2013-2015 Microchip Technology Inc. DS00001987A-page 131

LAN8740A/LAN8740Ai NOTES: DS00001987A-page 132  2013-2015 Microchip Technology Inc.

LAN8740A/LAN8740Ai THE MICROCHIP WEB SITE Microchip provides online support via our WWW site at www.microchip.com. This web site is used as a means to make files and information easily available to customers. Accessible by using your favorite Internet browser, the web site con- tains the following information: • Product Support – Data sheets and errata, application notes and sample programs, design resources, user’s guides and hardware support documents, latest software releases and archived software • General Technical Support – Frequently Asked Questions (FAQ), technical support requests, online discussion groups, Microchip consultant program member listing • Business of Microchip – Product selector and ordering guides, latest Microchip press releases, listing of semi- nars and events, listings of Microchip sales offices, distributors and factory representatives CUSTOMER CHANGE NOTIFICATION SERVICE Microchip’s customer notification service helps keep customers current on Microchip products. Subscribers will receive e-mail notification whenever there are changes, updates, revisions or errata related to a specified product family or development tool of interest. To register, access the Microchip web site at www.microchip.com. Under “Support”, click on “Customer Change Notifi- cation” and follow the registration instructions. CUSTOMER SUPPORT Users of Microchip products can receive assistance through several channels: • Distributor or Representative • Local Sales Office • Field Application Engineer (FAE) • Technical Support Customers should contact their distributor, representative or field application engineer (FAE) for support. Local sales offices are also available to help customers. A listing of sales offices and locations is included in the back of this docu- ment. Technical support is available through the web site at: http://microchip.com/support  2013-2015 Microchip Technology Inc. DS00001987A-page 133

LAN8740A/LAN8740Ai PRODUCT IDENTIFICATION SYSTEM To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office. PART NO. [X] XX [XX](1) Examples: Device Temperature Package Tape and a) LAN8740A-EN 0°C to +70°C, Range Reel Option (32-pin), Tray b) LAN8740Ai-EN Device: LAN8740A -40°C to +85°C, (32-pin), Tray Temperature Blank = 0°C to +70°C Range: i = -40°C to +85°C c) LAN8740A-EN-TR 0°C to +70°C, (32-pin), Package: EN = VQFN (32-pin) Tape and Reel Tape and Reel Blank = Standard packaging (tray) Option: TR = Tape and Reel(1) Note1: Tape and Reel identifier only appears in the catalog part number description. This identifier is used for ordering purposes and is not printed on the device package. Check with your Microchip Sales Office for package availability with the Tape and Reel option. Reel size is 4,000. DS00001987A-page 134  2013-2015 Microchip Technology Inc.

Note the following details of the code protection feature on Microchip devices: • Microchip products meet the specification contained in their particular Microchip Data Sheet. • Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the intended manner and under normal conditions. • There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data Sheets. Most likely, the person doing so is engaged in theft of intellectual property. • Microchip is willing to work with the customer who is concerned about the integrity of their code. • Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not mean that we are guaranteeing the product as “unbreakable.” Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act. Information contained in this publication regarding device applications and the like is provided only for your convenience and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. MICROCHIP MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL, STATUTORY OR OTHERWISE, RELATED TO THE INFORMATION, INCLUDING BUT NOT LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE, MERCHANTABILITY OR FITNESS FOR PURPOSE. Microchip disclaims all liability arising from this information and its use. Use of Micro- chip devices in life support and/or safety applications is entirely at the buyer’s risk, and the buyer agrees to defend, indemnify and hold harmless Microchip from any and all damages, claims, suits, or expenses resulting from such use. No licenses are conveyed, implicitly or otherwise, under any Microchip intellectual property rights unless otherwise stated. Trademarks The Microchip name and logo, the Microchip logo, dsPIC, FlashFlex, flexPWR, JukeBlox, KEELOQ, KEELOQ logo, Kleer, LANCheck, MediaLB, MOST, MOST logo, MPLAB, OptoLyzer, PIC, PICSTART, PIC32 logo, RightTouch, SpyNIC, SST, SST Logo, SuperFlash and UNI/O are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. The Embedded Control Solutions Company and mTouch are registered trademarks of Microchip Technology Incorporated in the U.S.A. Analog-for-the-Digital Age, BodyCom, chipKIT, chipKIT logo, CodeGuard, dsPICDEM, dsPICDEM.net, ECAN, In-Circuit Serial Programming, ICSP, Inter-Chip Connectivity, KleerNet, KleerNet logo, MiWi, motorBench, MPASM, MPF, MPLAB Certified logo, MPLIB, MPLINK, MultiTRAK, NetDetach, Omniscient Code Generation, PICDEM, PICDEM.net, PICkit, PICtail, RightTouch logo, REAL ICE, SQI, Serial Quad I/O, Total Endurance, TSHARC, USBCheck, VariSense, ViewSpan, WiperLock, Wireless DNA, and ZENA are trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. SQTP is a service mark of Microchip Technology Incorporated in the U.S.A. Silicon Storage Technology is a registered trademark of Microchip Technology Inc. in other countries. GestIC is a registered trademark of Microchip Technology Germany II GmbH & Co. KG, a subsidiary of Microchip Technology Inc., in other countries. All other trademarks mentioned herein are property of their respective companies. © 2013-2015, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved. ISBN: 978-1-63277-636-5 QUALITY MANAGEMENT SYSTEM Microchip received ISO/TS-16949:2009 certification for its worldwide headquarters, design and wafer fabrication facilities in Chandler and CERTIFIED BY DNV Tempe, Arizona; Gresham, Oregon and design centers in California and India. The Company’s quality system processes and procedures are for its PIC® MCUs and dsPIC® DSCs, KEELOQ® code hopping == ISO/TS 16949 == devices, Serial EEPROMs, microperipherals, nonvolatile memory and analog products. In addition, Microchip’s quality system for the design and manufacture of development systems is ISO 9001:2000 certified.  2013-2015 Microchip Technology Inc. DS00001987A-page 135

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Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: M icrochip: LAN8740A-EN LAN8740A-EN-TR LAN8740AI-EN-TR LAN8740AI-EN