SP3485 3.3V Low Power Half-Duplex RS-485 Transceiver with 10Mbps Data Rate Description FEATURES The SP3485 device is a 3.3V low power half-duplex transceiver that ■■ RS-485 and RS-422 transceiver meets the specifications of the RS-485 and RS-422 serial protocols. ■■ Operates from a single 3.3V supply This device is pin-to-pin compatible with the MaxLinear SP481, ■■ Interoperable with 5.0V logic SP483 and SP485 devices as well as popular industry standards. The ■■ Driver/receiver enable SP3485 can meet the electrical specifications of the RS-485 and RS- ■■ -7V to +12V common-mode input voltage range 422 serial protocols up to 10Mbps under load. ■■ Allows up to 32 transceivers on the serial bus ■■ Compatibility with industry standard 75176 pinout ■■ Driver output short-circuit protection Ordering Information - Back Page Block Diagram RO 1 R 8 V CC RE 2 7 B DE 3 6 A DI 4 D 5 GND SP3485 REV 2.0.1 1/9

SP3485 Absolute Maximum Ratings These are stress ratings only and functional operation of the Storage Temperature ...................................-65˚C to 150˚C device at these ratings or any other above those indicated Maximum Junction Temperature, T ..........................125˚C J in the operation sections of the specifications below is not implied. Exposure to absolute maximum rating conditions Power Dissipation ....................................................600mW for extended periods of time may affect reliability. (derate 6.90mW/°C above 70°C) V ...............................................................................6.0V CC Operating Conditions Input Voltages Package Power Dissipation Logic .....................................-0.3V to 6.0V 8-pin NSOIC Ѳ ................................................128.4˚C/W JA Drivers ..................................-0.3V to 6.0V Receivers ...........................................±15V ESD Rating Output Voltages Human Body Model (HBM) ..........................................±2kV Drivers ...............................................±15V Receivers ..............................-0.3V to 6.0V Electrical Characteristics Unless otherwise noted: T = T to T and V = 3.3V ±5%. AMB MIN MAX CC PARAMETERS MIN. TYP. MAX. UNITS CONDITIONS SP3485 Driver DC Characteristics Differential output voltage Vcc Volts Unloaded; R = ∞Ω ; Figure 1 Differential output voltage 2 Vcc Volts With Load; R = 50Ω (RS-422); Figure 1 Differential output voltage 1.5 Vcc Volts With Load; R = 27Ω (RS-485); Figure 1 Change in magnitude of driver differential output 0.2 Volts R = 27Ω or R = 50Ω; Figure 1 voltage for complimentary states Driver common mode output voltage 3 Volts R = 27Ω or R = 50Ω; Figure 1 Input high voltage 2.0 Volts Applies to DE, DI, RE Input low voltage 0.8 Volts Applies to DE, DI, RE Input current ±10 µA Applies to DE, DI, RE Driver short circuit current VOUT = HIGH ±250 mA -7V ≤ VO ≤ +12V; Figure 8 Driver short circuit current VOUT = LOW ±250 mA -7V ≤ VO ≤ +12V; Figure 8 SP3485 Driver AC Characteristics Maximum data rate 10 Mbps RE = VCC, DE = VCC Driver input to output, tPLH 17 60 ns Figures 2 & 9 Driver input to output, tPHL 17 60 ns Figures 2 & 9 Differential driver skew 2 10 ns |tDO1- tDO2|, Figures 2 and 10 Driver rise or fall time 5 20 ns From 10%-90%; Figures 3 and 10 Driver enable to output high 35 120 ns Figures 4 and 11 Driver enable to output low 30 120 ns Figures 5 and 11 Driver disable time from low 20 120 ns Figures 5 and 11 Driver disable time from high 20 120 ns Figures 4 and 11 Driver enable from shutdown to output high, tPSH 250 ns CL = 50pF, RL = 500Ω. Driver enable from shutdown to output low, tPSL 250 ns Figures 4, 5, and 11 Time to shutdown, tSHDN 50 200 600 ns Notes 1 and 2 REV 2.0.1 2/9

SP3485 Electrical Characteristics (Continued) Unless otherwise noted: T = T to T and V = 3.3V ±5%. AMB MIN MAX CC PARAMETERS MIN. TYP. MAX. UNITS CONDITIONS SP3485 Receiver DC Characteristics Differential input threshold -0.2 0.2 Volts -7V ≤ VCM ≤ 12V Input hysteresis 20 mV VCM = 0V Output voltage HIGH Vcc-0.4 Volts VID = 200mV, -1.5mA Output voltage LOW 0.4 Volts VID = -200mV, 2.5mA Three-state (high impedance) output current ±1 µA 0V ≤ VO ≤ VCC; RE = VCC Input resistance 12 kΩ -7V ≤ VCM ≤ 12V Input current (A, B); VIN = 12V 1.0 mA DVIEN == 01V2,V VCC = 0V or 3.6V, Input current (A, B); VIN = -7V -0.8 mA DVIEN == 0-7VV, VCC = 0V or 3.6V, Short circuit current 7 60 mA 0V ≤ VCM ≤ VCC SP3485 Receiver AC Characteristics Maximum data rate 10 Mbps RE = 0V, DE = 0V Receiver input to output, tPLH 40 100 ns Figures 6 and 12 Receiver input to output, tPLH 70 ns TFAigMuBr e=s 265 a°Cnd, V1c2c = 3.3V, Receiver input to output, tPHL 35 100 ns Figures 6 and 12 Receiver input to output, tPHL 70 ns TFAigMuBr e=s 265 a°Cnd, V1c2c = 3.3V, Differential receiver skew 4 ns tRSKEW = |tRPHL- tRPLH|, Figures 6 and 12 Figures 7 and 13, Receiver enable to output low 10 60 ns S1 closed, S2 open Figures 7 and 13, Receiver enable to output high 10 60 ns S2 closed, S1 open Figures 7 and 13, Receiver disable from low 10 60 ns S1 closed, S2 open Figures 7 and 13, Receiver disable from high 10 60 ns S2 closed, S1 open Receiver enable from shutdown to output high, tPRSH 1800 ns CL = 15pF, RL = 1kΩ. Figures 7 and 13 Receiver enable from shutdown to output low, tPRSL 1800 ns Time to shutdown, tSHDN 50 200 600 ns Notes 1 and 2 Power Requirements Supply current , no load 425 2000 µA RE, DI = 0V or VCC ; DE = VCC Supply current , no load 300 1500 µA RE = 0V, DI = 0V or VCC, DE = 0V NOTES: 1. The transceivers are put into shutdown by gringing RE high and DE low simultaneously for at least 600ns. If the control inputs are in this state for less than 50ns, the device is guaranteed to not enter shutdown. If the enable inputs are held in this state for at least 600ns, the device is assured to be in shutdown. Note that the receiver and driver times increase significantly when coming out of shutdown. 2. This spec is guaranteed by design and bench characterization. REV 2.0.1 3/9

SP3485 Pin Functions Pin Name Description 1 RO Receiver output 2 RE Receiver output enable active LOW RO 1 R 8 V CC 3 DE Driver output enable active HIGH RE 2 7 B 4 DI Driver input 5 GND Ground connection DE 3 6 A 6 A Non-inverting driver output / receiver input DI 4 D 5 GND 7 B Inverting driver output / receiver input 8 VCC Positive supply SP3485 Pinout (Top View) REV 2.0.1 4/9

SP3485 Test Circuits R C L R V D 15pF 54LΩ OUT D OD (NOTE 2) GENERATOR (NOTE 1) 50Ω R V VCC Vcc OC Figure 1: Driver DC Test Load Circuit Figure 2: Driver Propagation Delay Test Circuit S1 D OUT D CL 6R0L Ω= OUT C (NL O= T5E0p 2F) RL = 110Ω GENERATOR GENERATOR (NOTE 1) 50Ω (NOTE 1) 50Ω VCC CL = 15pF (NOTE 2) Figure 3: Driver Differential Output Delay Figure 4: Driver Enable and Disable Timing Circuit, and Transition Time Circuit. Output High VCC RL = 110Ω S1 OUT VID R 0V OR 3V D OUT GENERATOR 50Ω (NOTE 1) CL = 15pF CL = 50pF (NOTE 2) (NOTE 2) GENERATOR 50Ω (NOTE 1) 1.5V 0V Figure 5: Driver Enable and Disable Timing Circuit, Figure 6: Receiver Propagation Delay Test Circuit Output Low S1 S3 1.5V 1k VCC DE = 0 or Vcc -1.5V VID R S2 A IOS D DI = 0 or Vcc D CL = 15pF (NOTE 2) B GENERATOR (NOTE 1) 50Ω -7V to +12V V Figure 7: Receiver Enable and Disable Timing Circuit Figure 8: Driver Short Circuit Current Limit Test NOTES 1: The input pulse is supplied by a generator with the following characteristics: PRR = 250kHz, 50% duty cycle, tR < 6.0ns, ZO = 50Ω. 2: CL includes probe and stray capacitance. REV 2.0.1 5/9

SP3485 Switching Waveforms 3V INPUT 1.5V 1.5V 3V 0V IN 1.5V 1.5V VOH tPLH tPHL 0V Y OUTPUT VOM VOM tDO1 tDO2 VOL 2.0V tPHL tPLH 90% 90% VOH 50% 50% Z OUTPUT VOM VOM OUT 10% 10% VOL -2.0V tTD tTD VOM = VOH 2+ VOL ≈ 1.5V Figure 9: Driver Propagation Delay Waveforms Figure 10: Driver Differential Output Delay and Transition Time Waveforms 3V DE 1.5V 1.5V 0V tPZH tPSH tPHZ VOH 0.25V 3V OUTPUT VOM INPUT 1.5V 1.5V HIGH 0V 0V tPZL tRPLH tRPHL VCC tPSL tPLZ VCC OULOTPWUT VOM OUTPUT VOM VOM VOL 0.25V 0V VOM = VOH 2+ VOL ≈ 1.5V VOM = V2CC Figure 11: Driver Enable and Disable Timing Waveforms Figure 12: Receiver Propagation Delay Waveforms S1 is open S1 is closed S2 is closed S2 is open S3 = 1.5V S3 = -1.5V 3V 3V RE 1.5V 1.5V RE 1.5V 1.5V 0V 0V tPRHZ ttPRZH tPRLZ ttPPRRZSLL PRSH VOH 10% VCC OUTPUT 1.5V OUTPUT 1.5V 10% 0V VOL Figure 13: Receiver Enable and Disable Waveforms REV 2.0.1 6/9

SP3485 Description Low Power Shutdown Mode Low-power shutdown mode is initiated by bringing both The SP3485 is a member in the family of 3.3V low power half- RE high and DE low. In shutdown, the devices typically duplex transceivers that meet the electrical specifications of draw only 50nA of supply current. RE and DE can be the RS-485 and RS-422 serial protocols. This device is pin- driven simultaneously; the part is guaranteed not to enter to-pin compatible with the MaxLinear SP481, SP483 and shutdown if RE is high and DE is low for less than 50ns. If SP485 devices as well as popular industry standards. The the inputs are in this state for at least 600ns, the parts are SP3485 feature MaxLinear’s BiCMOS process allowing low guaranteed to enter shutdown. power operationwithout sacrificing performance. Enable times t , t , t and t assume the part PRZH PZH PRZL PZL Driver was not in a low-power shutdown state. Enable times t , PRSH The driver outputs of the SP3485 are differential outputs t t and t assume the parts were shut down. It PSH, PRSL PSL meeting the RS-485 and RS-422 standards. The typical takes drivers and receivers longer to become enabled from voltage output swing with no load will be 0 volts to 3.3 Volts. low-power shutdown mode (t , t , t , t ) than PRSH PSH PRSL PSL With a load of 54Ω across the differential outputs, the drivers from driver/receiver-disable mode (t , t , t , t ). PRZH PZH PRZL PZL can maintain greater than 1.5V voltage levels. The driver of the SP3485 has a driver enable control line which is active HIGH. A logic HIGH on DE (pin 3) will enable INPUTS OUTPUTS the differential driver outputs. A logic LOW on the DE (pin RE DE DI B A 3) will tri-state the driver outputs. X 1 1 0 1 The driver of the SP3485 operates up to 10Mbps. The X 1 0 1 0 250mA I maximum limit on the driver output allows the SC 0 0 X High-Z SP3485 to withstand an infinite short circuit over the -7.0V 1 0 X Shutdown to 12V common mode range without catastrophic damage to the IC. Table 1: Transmit Function Truth Table Receiver The SP3485 receiver has differential inputs with an input sensitivity of ±200mV. Input impedance of the receiver is 12kΩ minimum. A wide common mode range of -7V to INPUTS OUTPUTS 12V allows for large ground potential differences between RE DE VA - VB RO systems. The receiver is equipped with a fail-safe feature 0 X -50mV 1 that guarantees the receiver output will be in a HIGH state 0 X -200mV 0 when the input is left unconnected. The receiver of the SP3485 operates up to 10Mbps. X X Open/Shorted 1 1 1 X High-Z The receiver of the SP3485 has an enable control line which is active LOW. A logic LOW on RE (pin 2) will enable 1 0 X Shutdown the differential receiver. A logic HIGH on RE (pin 2) of the SP3485 will disable the receiver. Table 2: Receive Function Truth Table REV 2.0.1 7/9

SP3485 Mechanical Dimensions NSOIC8 Top View Side View Front View Drawing No: POD-00000108 Revision: A REV 2.0.1 8/9

SP3485 Ordering Information(1) Part Number Operating Temperature Range Lead-Free Package Packaging Method SP3485CN-L Tube 0°C to 70°C SP3485CN-L/TR Reel Yes(2) 8-pin SOIC SP3485EN-L Tube -40°C to 85°C SP3485EN-L/TR Reel NOTE: 1. Refer to www.exar.com/SP3485 for most up-to-date Ordering Information. 2. Visit www.exar.com for additional information on Environmental Rating. Revision History Revision Date Description 10/15/02 -- Legacy Sipex Datasheet Convert to Exar Format. Update ordering information and add new Figure 8 - Driver Short 06/19/12 1.0.0 Circuit Current Limit Test Circuit. Remove EOL device SP3481. Update logo. Update description paragraph on page 1. Update timing specifications in electrical characteristics table on pages 2 and 3. Add Driver and Receiver Enable from Shutdown timing information on pages 3 and 4. Update typical supply current information 06/27/16 2.0.0 on page 4. Update Figures 2, 4, 6, and 8. Update Figures 11 and 13 to add shutdown timing labels. Add low power shutdown section to page 7. Update transmit and receive truth tables on page 7. Update Receiver section on page 7. Remove GND from Differential Output Voltage min (page 2). Added maximum junction 09/06/17 2.0.1 temperature, package power dissipation and ESD rating. Update to MaxLinear logo, update format and ordering information table. Corporate Headquarters: High Performance Analog: 5966 La Place Court 48720 Kato Road Suite 100 Fremont, CA 94538 Carlsbad, CA 92008 Tel.: +1 (510) 668-7000 Tel.:+1 (760) 692-0711 Fax: +1 (510) 668-7001 Fax: +1 (760) 444-8598 Email: serialtechsupport@exar.com www.maxlinear.com www.exar.com The content of this document is furnished for informational use only, is subject to change without notice, and should not be construed as a commitment by MaxLinear, Inc.. MaxLinear, Inc. assumes no responsibility or liability for any errors or inaccuracies that may appear in the informational content contained in this guide. Complying with all applicable copyright laws is the responsibility of the user. Without limiting the rights under copyright, no part of this document may be reproduced into, stored in, or introduced into a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise), or for any purpose, without the express written permission of MaxLinear, Inc. Maxlinear, Inc. does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect its safety or effectiveness. Products are not authorized for use in such applications unless MaxLinear, Inc. receives, in writing, assurances to its satisfaction that: (a) the risk of injury or damage has been minimized; (b) the user assumes all such risks; (c) potential liability of MaxLinear, Inc. is adequately protected under the circumstances. MaxLinear, Inc. may have patents, patent applications, trademarks, copyrights, or other intellectual property rights covering subject matter in this document. Except as expressly provided in any written license agreement from MaxLinear, Inc., the furnishing of this document does not give you any license to these patents, trademarks, copyrights, or other intellectual property. Company and product names may be registered trademarks or trademarks of the respective owners with which they are associated. © 2012-2017 MaxLinear, Inc. All rights reserved SP3485_DS_090617 REV 2.0.1 9/9

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