PCF8574; PCF8574A Remote 8-bit I/O expander for I2C-bus with interrupt Rev. 5 — 27 May 2013 Product data sheet 1. General description The PCF8574/74A provides general-purpose remote I/O expansion via the two-wire bidirectional I2C-bus (serial clock (SCL), serial data (SDA)). The devices consist of eight quasi-bidirectional ports, 100kHz I2C-bus interface, three hardware address inputs and interrupt output operating between 2.5V and 6V. The quasi-bidirectional port can be independently assigned as an input to monitor interrupt status or keypads, or as an output to activate indicator devices such as LEDs. System master can read from the input port or write to the output port through a single register. The low current consumption of 2.5A (typical, static) is great for mobile applications and the latched output ports directly drive LEDs. The PCF8574 and PCF8574A are identical, except for the different fixed portion of the slave address. The three hardware address pins allow eight of each device to be on the same I2C-bus, so there can be up to 16 of these I/O expanders PCF8574/74A together on the same I2C-bus, supporting up to 128I/Os (for example, 128LEDs). The active LOW open-drain interrupt output (INT) can be connected to the interrupt logic of the microcontroller and is activated when any input state differs from its corresponding input port register state. It is used to indicate to the microcontroller that an input state has changed and the device needs to be interrogated without the microcontroller continuously polling the input register via the I2C-bus. The internal Power-On Reset (POR) initializes the I/Os as inputs with a weak internal pull-up 100A current source. 2. Features and benefits  I2C-bus to parallel port expander  100kHz I2C-bus interface (Standard-mode I2C-bus)  Operating supply voltage 2.5V to 6V with non-overvoltage tolerant I/O held to V DD with 100A current source  8-bit remote I/O pins that default to inputs at power-up  Latched outputs directly drive LEDs  Total package sink capability of 80mA  Active LOW open-drain interrupt output  Eight programmable slave addresses using three address pins  Low standby current (2.5A typical)  40C to +85C operation  ESD protection exceeds 2000V HBM per JESD22-A114 and 1000V CDM per JESD22-C101

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt  Latch-up testing is done to JEDEC standard JESD78 which exceeds 100mA  Packages offered: DIP16, SO16, SSOP20 3. Applications  LED signs and displays  Servers  Key pads  Industrial control  Medical equipment  PLC  Cellular telephones  Mobile devices  Gaming machines  Instrumentation and test measurement 4. Ordering information Table 1. Ordering info rmation Type number Topside mark Package Name Description Version PCF8574P PCF8574P DIP16 plastic dual in-line package; 16 leads (300mil) SOT38-4 PCF8574AP PCF8574AP PCF8574T/3 PCF8574T SO16 plastic small outline package; 16leads; bodywidth7.5mm SOT162-1 PCF8574AT/3 PCF8574AT PCF8574TS/3 8574TS SSOP20 plastic shrink small outline package; 20leads; SOT266-1 bodywidth4.4mm PCF8574ATS/3 8574A 4.1 Ordering options Table 2. Ordering opt ions Type number Orderable Package Packing method Minimum Temperature range partnumber order quantity PCF8574P PCF8574P,112 DIP16 Standard marking 1000 T =40C to +85C amb *IC’stube - DSC bulk pack PCF8574AP PCF8574AP,112 DIP16 Standard marking 1000 T =40C to +85C amb *IC’stube - DSC bulk pack PCF8574T/3 PCF8574T/3,512 SO16 Standard marking 1920 T =40C to +85C amb * tube drypack PCF8574T/3,518 SO16 Reel 13” Q1/T1 1000 T =40C to +85C amb *standard mark SMD drypack PCF8574AT/3 PCF8574AT/3,512 SO16 Standard marking 1920 T =40C to +85C amb * tube drypack PCF8574AT/3,518 SO16 Reel 13” Q1/T1 1000 T =40C to +85C amb *standard mark SMD drypack PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 2 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt Table 2. Ordering options …continued Type number Orderable Package Packing method Minimum Temperature range partnumber order quantity PCF8574TS/3 PCF8574TS/3,112 SSOP20 Standard marking 1350 T =40C to +85C amb *IC’stube - DSC bulk pack PCF8574TS/3,118 SSOP20 Reel 13” Q1/T1 2500 T =40C to +85C amb *standard mark SMD PCF8574ATS/3 PCF8574ATS/3,118 SSOP20 Reel 13” Q1/T1 2500 T =40C to +85C amb *standard mark SMD 5. Block diagram PCF8574 PCF8574A INTERRUPT INT LP FILTER LOGIC A0 P0 A1 P1 A2 P2 SCL INPUT I2C-BUS SHIFT 8 bits I/O P3 FILTER CONTROL REGISTER PORT P4 SDA P5 P6 P7 write pulse read pulse POWER-ON VDD RESET VSS 002aad624 Fig 1. Block diagram VDD write pulse IOH 100 μA Itrt(pu) data from Shift Register D Q FF P0 to P7 CI IOL S power-on reset VSS D Q FF read pulse CI S to interrupt logic data to Shift Register 002aac109 Fig 2. Simplified schematic diagram of P0 to P7 PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 3 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt 6. Pinning information 6.1 Pinning A0 1 16 VDD A1 2 15 SDA INT 1 20 P7 SCL 2 19 P6 A2 3 14 SCL A0 1 16 VDD n.c. 3 18 n.c. P0 4 PCF8574P 13 INT A1 2 15 SDA SDA 4 17 P5 PCF8574AP A2 3 14 SCL VDD 5 PCF8574TS/3 16 P4 P1 5 12 P7 P0 4 PCF8574T/3 13 INT A0 6 PCF8574ATS/3 15 VSS P2 6 11 P6 P1 5 PCF8574AT/3 12 P7 A1 7 14 P3 P2 6 11 P6 n.c. 8 13 n.c. P3 7 10 P5 P3 7 10 P5 A2 9 12 P2 VSS 8 9 P4 VSS 8 9 P4 P0 10 11 P1 002aad625 002aad626 002aad627 Fig 3. Pin configuration for DIP16 Fig 4. Pin configuration for SO16 Fig 5. Pin configuration for SSOP20 6.2 Pin description Table 3. Pin description Symbol Pin Description DIP16, SO16 SSOP20 A0 1 6 address input 0 A1 2 7 address input 1 A2 3 9 address input 2 P0 4 10 quasi-bidirectional I/O 0 P1 5 11 quasi-bidirectional I/O 1 P2 6 12 quasi-bidirectional I/O 2 P3 7 14 quasi-bidirectional I/O 3 V 8 15 supply ground SS P4 9 16 quasi-bidirectional I/O 4 P5 10 17 quasi-bidirectional I/O 5 P6 11 19 quasi-bidirectional I/O 6 P7 12 20 quasi-bidirectional I/O 7 INT 13 1 interrupt output (active LOW) SCL 14 2 serial clock line SDA 15 4 serial data line V 16 5 supply voltage DD n.c. - 3, 8, 13, 18 not connected PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 4 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt 7. Functional description Refer to Figure 1 “Block diagram”. 7.1 Device address Following a START condition, the bus master must send the address of the slave it is accessing and the operation it wants to perform (read or write). The address format of the PCF8574/74A is shown in Figure6. Slave address pins A2, A1 and A0 are held HIGH or LOW to choose one of eight slave addresses. To conserve power, no internal pull-up resistors are incorporated on A2, A1 or A0, so they must be externally held HIGH or LOW. The address pins (A2, A1, A0) can connect to V or V directly or through resistors. DD SS R/W R/W slave address slave address 0 1 0 0 A2 A1 A0 0 0 1 1 1 A2 A1 A0 0 fixed hardware fixed hardware selectable selectable 002aad628 002aad629 a. PCF8574 b. PCF8574A Fig 6. PCF8574 and PCF8574A slave addresses The last bit of the first byte defines the operation to be performed. When set to logic1 a read is selected, while a logic0 selects a write operation (write operation is shown in Figure6). 7.1.1 Address maps The PCF8574 and PCF8574A are functionally the same, but have a different fixed portion (A6 to A3) of the slave address. This allows eight of the PCF8574 and eight of the PCF8574A to be on the same I2C-bus without address conflict. Table 4. PCF8574 address map Pin connectivity Address of PCF8574 Address byte value 7-bit hexadecimal A2 A1 A0 A6 A5 A4 A3 A2 A1 A0 R/W Write Read address without R/W V V V 0 1 0 0 0 0 0 - 40h 41h 20h SS SS SS V V V 0 1 0 0 0 0 1 - 42h 43h 21h SS SS DD V V V 0 1 0 0 0 1 0 - 44h 45h 22h SS DD SS V V V 0 1 0 0 0 1 1 - 46h 47h 23h SS DD DD V V V 0 1 0 0 1 0 0 - 48h 49h 24h DD SS SS V V V 0 1 0 0 1 0 1 - 4Ah 4Bh 25h DD SS DD V V V 0 1 0 0 1 1 0 - 4Ch 4Dh 26h DD DD SS V V V 0 1 0 0 1 1 1 - 4Eh 4Fh 27h DD DD DD PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 5 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt Table 5. PCF8574A address map Pin connectivity Address of PCF8574A Address byte value 7-bit hexadecimal A2 A1 A0 A6 A5 A4 A3 A2 A1 A0 R/W Write Read address without R/W V V V 0 1 1 1 0 0 0 - 70h 71h 38h SS SS SS V V V 0 1 1 1 0 0 1 - 72h 73h 39h SS SS DD V V V 0 1 1 1 0 1 0 - 74h 75h 3Ah SS DD SS V V V 0 1 1 1 0 1 1 - 76h 77h 3Bh SS DD DD V V V 0 1 1 1 1 0 0 - 78h 79h 3Ch DD SS SS V V V 0 1 1 1 1 0 1 - 7Ah 7Bh 3Dh DD SS DD V V V 0 1 1 1 1 1 0 - 7Ch 7Dh 3Eh DD DD SS V V V 0 1 1 1 1 1 1 - 7Eh 7Fh 3Fh DD DD DD 8. I/O programming 8.1 Quasi-bidirectional I/Os A quasi-bidirectional I/O is an input or output port without using a direction control register. Whenever the master reads the register, the value returned to master depends on the actual voltage or status of the pin. At power on, all the ports are HIGH with a weak 100A internal pull-up to V , but can be driven LOW by an internal transistor, or an external DD signal. The I/O ports are entirely independent of each other, but each I/O octal is controlled by the same read or write data byte. Advantages of the quasi-bidirectional I/O over totem pole I/O include: • Better for driving LEDs since the p-channel (transistor to V ) is small, which saves DD die size and therefore cost. LED drive only requires an internal transistor to ground, while the LED is connected to V through a current-limiting resistor. Totempole I/O DD have both n-channel and p-channel transistors, which allow solid HIGH and LOW output levels without a pull-up resistor — good for logic levels. • Simpler architecture — only a single register and the I/O can be both input and output at the same time. Totem pole I/O have a direction register that specifies the port pin direction and it is always in that configuration unless the direction is explicitly changed. • Doesnot require a command byte. The simplicity of one register (no need for the pointer register or, technically, the command byte) is an advantage in some embedded systems where every byte counts because of memory or bandwidth limitations. PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 6 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt There is only one register to control four possibilities of the port pin: Input HIGH, input LOW, output HIGH, or output LOW. Input HIGH: The master needs to write 1 to the register to set the port as an input mode if the device is not in the default power-on condition. The master reads the register to check the input status. If the external source pulls the port pin up to V or drives DD logic1, then the master will read the value of 1. Input LOW: The master needs to write 1 to the register to set the port to input mode if the device is not in the default power-on condition. The master reads the register to check the input status. If the external source pulls the port pin down to V or drives SS logic0, which sinks the weak 100A current source, then the master will read the value of 0. Output HIGH: The master writes 1 to the register. There is an additional ‘accelerator’ or strong pull-up current when the master sets the port HIGH. The additional strong pull-up is only active during the HIGH time of the acknowledge clock cycle. This accelerator current helps the port’s 100A current source make a faster rising edge into a heavily loaded output, but only at the start of the acknowledge clock cycle to avoid bus contention if an external signal is pulling the port LOW to V /driving the port with SS logic0 at the same time. After the half clock cycle there is only the 100A current source to hold the port HIGH. Output LOW: The master writes 0 to the register. There is a strong current sink transistor that holds the port pin LOW. A large current may flow into the port, which could potentially damage the part if the master writes a 0 to the register and an external source is pulling the port HIGH at the same time. VDD input HIGH weak 100 µA pull-up with current source output HIGH (inactive when resistor to VDD or output LOW) external drive HIGH accelerator pull-up P port P7 - P0 pull-down with output LOW resistor to VSS or external drive LOW input LOW VSS 002aah683 Fig 7. Simple quasi-bidirectional I/O PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 7 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt 8.2 Writing to the port (Output mode) The master (microcontroller) sends the START condition and slave address setting the last bit of the address byte to logic0 for the write mode. The PCF8574/74A acknowledges and the master then sends the data byte for P7 to P0 to the port register. As the clock line goes HIGH, the 8-bit data is presented on the port lines after it has been acknowledged by the PCF8574/74A. If a LOW is written, the strong pull-down turns on and stays on. If a HIGH is written, the strong pull-up turns on for 1⁄ of the clock cycle, then the line is held 2 HIGH by the weak current source. The master can then send a STOP or ReSTART condition or continue sending data. The number of data bytes that can be sent successively is not limited and the previous data is overwritten every time a data byte has been sent and acknowledged. Ensure a logic1 is written for any port that is being used as an input to ensure the strong external pull-down is turned off. SCL 1 2 3 4 5 6 7 8 9 slave address data 1 data 2 SDA S A6 A5 A4 A3 A2 A1 A0 0 A P7 P6 1 P4 P3 P2 P1 P0 A P7 P6 0 P4 P3 P2 P1 P0 A START condition R/W P5 P5 acknowledge acknowledge acknowledge from slave from slave from slave write to port tv(Q) tv(Q) data output from port DATA 1 VALID DATA 2 VALID P5 output voltage P5 pull-up output current Itrt(pu) IOH INT td(rst) 002aah349 Fig 8. Write mode (output) Simple code WRITE mode: <S> <slave address+write> <ACK> <data out> <ACK> <data out> <ACK> ... <dataout><ACK> <P> Remark: Bold type = generated by slave device. PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 8 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt 8.3 Reading from a port (Input mode) The port must have been previously written to logic1, which is the condition after power-on reset. To enter the Read mode the master (microcontroller) addresses the slave device and sets the last bit of the address byte to logic1 (address byte read). The slave will acknowledge and then send the data byte to the master. The master will NACK and then send the STOP condition or ACK and read the input register again. The read of any pin being used as an output will indicate HIGH or LOW depending on the actual state of the pin. If the data on the input port changes faster than the master can read, this data may be lost. The DATA 2 and DATA3 are lost because these data did not meet the setup time and holdtime (see Figure9). no acknowledge from master slave address data from port data from port SDA S A6 A5 A4 A3 A2 A1 A0 1 A DATA 1 A DATA 4 1 P START condition R/W acknowledge acknowledge STOP from slave from master condition read from port DATA 2 data at DATA 1 DATA 3 DATA 4 port th(D) tsu(D) INT tv(INT) trst(INT) trst(INT) 002aah383 A LOW-to-HIGH transition of SDA while SCL is HIGH is defined as the STOP condition (P). Transfer of data can be stopped at any moment by a STOP condition. When this occurs, data present at the last acknowledge phase is valid (output mode). Input data is lost. Fig 9. Read mode (input) Simple code for Read mode: <S> <slave address+read> <ACK> <data in> <ACK> ... <data in> <ACK> <data in> <NACK> <P> Remark: Bold type = generated by slave device. 8.4 Power-on reset When power is applied to V , an internal Power-On Reset (POR) holds the DD PCF8574/74A in a reset condition until V has reached V . At that point, the reset DD POR condition is released and the PCF8574/74A registers and I2C-bus/SMBus state machine will initialize to their default states of all I/Os to inputs with weak current source to V . DD Thereafter V must be lowered below V and back up to the operation voltage for DD POR power-on reset cycle. PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 9 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt 8.5 Interrupt output (INT) The PCF8574/74A provides an open-drain output (INT) which can be fed to a corresponding input of the microcontroller (see Figure10). As soon as a port input is changed, the INT will be active (LOW) and notify the microcontroller. An interrupt is generated at any rising or falling edge of the port inputs. After time t , the v(Q) signal INT is valid. The interrupt will reset to HIGH when data on the port is changed to the original setting or data is read or written by the master. In the Write mode, the interrupt may be reset (HIGH) on the rising edge of the acknowledge bit of the address byte and also on the rising edge of the write to port pulse. The interrupt will always be reset (HIGH) on the falling edge of the write to port pulse (see Figure8). The interrupt is reset (HIGH) in the Read mode on the rising edge of the read from port pulse (see Figure9). During the interrupt reset, any I/O change close to the read or write pulse may not generate an interrupt, or the interrupt will have a very short pulse. After the interrupt is reset, any change in I/Os will be detected and transmitted as an INT. At power-on reset all ports are in Input mode and the initial state of the ports is HIGH, therefore, for any port pin that is pulled LOW or driven LOW by external source, the interrupt output will be active (output LOW). VDD device 1 device 2 device 16 PCF8574 PCF8574 PCF8574A MICROCONTROLLER INT INT INT INT 002aad634 Fig 10. Application of multiple PCF8574/74As with interrupt PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 10 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt 9. Characteristics of the I2C-bus The I2C-bus is for 2-way, 2-wire communication between different ICs or modules. The two wires are a serial data line (SDA) and a serial clock line (SCL). Both lines must be connected to a positive supply via a pull-up resistor when connected to the output stages of a device. Data transfer may be initiated only when the bus is not busy. 9.1 Bit transfer One data bit is transferred during each clock pulse. The data on the SDA line must remain stable during the HIGH period of the clock pulse as changes in the data line at this time will be interpreted as control signals (see Figure11). SDA SCL data line change stable; of data data valid allowed mba607 Fig 11. Bit transfer 9.1.1 START and STOP conditions Both data and clock lines remain HIGH when the bus is not busy. A HIGH-to-LOW transition of the data line while the clock is HIGH is defined as the START condition (S). A LOW-to-HIGH transition of the data line while the clock is HIGH is defined as the STOP condition (P) (see Figure12). SDA SCL S P START condition STOP condition mba608 Fig 12. Definition of START and STOP conditions 9.2 System configuration A device generating a message is a ‘transmitter’; a device receiving is the ‘receiver’. The device that controls the message is the ‘master’ and the devices which are controlled by the master are the ‘slaves’ (see Figure13). PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 11 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt SDA SCL MASTER SLAVE SLAVE MASTER MASTER I2C-BUS TRANSMITTER/ RECEIVER TRANSMITTER/ TRANSMITTER TRANSMITTER/ MULTIPLEXER RECEIVER RECEIVER RECEIVER SLAVE 002aaa966 Fig 13. System configuration 9.3 Acknowledge The number of data bytes transferred between the START and the STOP conditions from transmitter to receiver is not limited. Each byte of eightbits is followed by one acknowledge bit (see Figure14). The acknowledge bit is an activeLOW level (generated by the receiving device) that indicates to the transmitter that the data transfer was successful. A slave receiver which is addressed must generate an acknowledge after the reception of each byte. Also a master must generate an acknowledge after the reception of each byte that has been clocked out of the slave transmitter. The device that wants to issue an acknowledge bit has to pull down the SDA line during the acknowledge clock pulse, so that the SDA line is stable LOW during the HIGH period of the acknowledge bit related clock pulse; set-up and hold times must be taken into account. A master receiver must signal an end of data to the transmitter by not generating an acknowledge on the last byte that has been clocked out of the slave. In this event, the transmitter must leave the data line HIGH to enable the master to generate a STOP condition. data output by transmitter not acknowledge data output by receiver acknowledge SCL from master 1 2 8 9 S clock pulse for START acknowledgement condition 002aaa987 Fig 14. Acknowledgement on the I2C-bus PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 12 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt 10. Application design-in information 10.1 Bidirectional I/O expander applications In the 8-bit I/O expander application shown in Figure15, P0 and P1 are inputs, and P2toP7 are outputs. When used in this configuration, during a write, the input (P0 and P1) must be written as HIGH so the external devices fully control the input ports. The desired HIGH or LOW logic levels may be written to the ports used as outputs (P2 to P7). If 10A internal output HIGH is not enough current source, the port needs external pull-up resistor. During a read, the logic levels of the external devices driving the input ports (P0 and P1) and the previous written logic level to the output ports (P2 to P7) will be read. The GPIO also has an interrupt line (INT) that can be connected to the interrupt logic of the microcontroller. By sending an interrupt signal on this line, the remote I/O informs the microprocessor that there has been a change of data on its ports without having to communicate via the I2C-bus. VDD VDD VDD SDA P0 temperature sensor CORE SCL P1 battery status PROCESSOR INT P2 control for latch P3 control for switch P4 control for audio A0 P5 control for camera A1 P6 control for MP3 A2 P7 002aah384 Fig 15. Bidirectional I/O expander application 10.2 How to read and write to I/O expander (example) In the application example of PCF8574 shown in Figure15, the microcontroller wants to control the P3switch ON and the P7 LED ON when the temperature sensor P0 changes. 1. When the system power on: Core Processor needs to issue an initial command to set P0 and P1 as inputs and P[7:2] as outputs with value 101000 (LED off, MP3 off, camera on, audio off, switchoff and latch off). 2. Operation: When the temperature changes above the threshold, the temperature sensor signal will toggle from HIGH to LOW. The INT will be activated and notifies the ‘core processor’ that there have been changes on the input pins. Read the input register. IfP0=0 (temperature sensor has changed), then turn on LED and turn on switch. 3. Software code: //System Power on // write to PCF8574 with data 1010 0011b to set P[7:2] outputs and P[1:0] inputs <S> <0100 0000> <ACK> <1010 0011> <ACK> <P>//Initial setting for PCF9574 PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 13 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt while (INT == 1); //Monitor the interrupt pin. If INT = 1 do nothing //When INT = 0 then read input ports <S> <slave address read> <ACK> <1010 0010> <NACK> <P> //Read PCF8574 data If (P0 == 0) //Temperature sensor activated { // write to PCF8574 with data 0010 1011b to turn on LED (P7), on Switch (P3) and keep P[1:0] as input ports. <S> <0100 0000> <ACK> <0010 1011> <ACK> <P> // Write to PCF8574 } 10.3 High current-drive load applications The GPIO has a minimum guaranteed sinking current of 10mA per bit at 5V. In applications requiring additional drive, two port pins may be connected together to sink up to 20mA current. Both bits must then always be turned on or off together. Up to fivepins can be connected together to drive 80mA, which is the device recommended total limit. Each pin needs its own limiting resistor as shown in Figure16 to prevent damage to the device should all ports not be turned on at the same time. VDD VDD VDD SDA P0 CORE SCL P1 PROCESSOR INT P2 P3 LOAD P4 A0 P5 A1 P6 A2 P7 002aah385 Fig 16. High current-drive load application 10.4 Migration path NXP offers newer, more capable drop-in replacements for the PCF8574/74A in newer space-saving packages. Table 6. Migration pa th Type number I2C-bus Voltage range Number of Interrupt Reset Total package frequency addresses sink current perdevice PCF8574/74A 100kHz 2.5V to 6V 8 yes no 80mA PCA8574/74A 400kHz 2.3V to 5.5V 8 yes no 200mA PCA9674/74A 1MHz Fm+ 2.3V to 5.5V 64 yes no 200mA PCA9670 1MHz Fm+ 2.3V to 5.5V 64 no yes 200mA PCA9672 1MHz Fm+ 2.3V to 5.5V 16 yes yes 200mA PCA9670 replaces the interrupt output of the PCA9674 with hardware reset input to retain the maximum number of addresses and the PCA9672 replaces address A2 of the PCA9674 with hardware reset input to retain the interrupt but limit the number of addresses. PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 14 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt 11. Limiting values Table 7. Limiting values In accordance with the Absolute Maximum Rating System (IEC 60134). Symbol Parameter Conditions Min Max Unit V supply voltage 0.5 +7 V DD I supply current - 100 mA DD I ground supply current - 100 mA SS V input voltage V 0.5 V +0.5 V I SS DD I input current - 20 mA I I output current - 25 mA O P total power dissipation - 400 mW tot P/out power dissipation per output - 100 mW T maximum junction temperature - 125 C j(max) T storage temperature 65 +150 C stg T ambient temperature operating 40 +85 C amb 12. Thermal characteristics Table 8. Thermal characteristics Symbol Parameter Conditions Typ Unit R thermal resistance from junction SO16 package 115 C/W th(j-a) to ambient SSOP20 package 136 C/W PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 15 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt 13. Static characteristics Table 9. Static charac teristics V =2.5V to 6V; V =0V; T =40C to +85C; unless otherwise specified. DD SS amb Symbol Parameter Conditions Min Typ Max Unit Supply V supply voltage 2.5 - 6.0 V DD I supply current operating mode; V =6V; noload; - 40 100 A DD DD V =V orV ; f =100kHz I DD SS SCL I standby current standby mode; V =6V; noload; - 2.5 10 A stb DD V =V orV I DD SS V power-on reset voltage V =6V; noload; V =V orV [1] - 1.3 2.4 V POR DD I DD SS Input SCL; input/output SDA V LOW-level input voltage 0.5 - +0.3V V IL DD V HIGH-level input voltage 0.7V - V +0.5 V IH DD DD I LOW-level output current V =0.4V 3 - - mA OL OL I leakage current V =V orV 1 - +1 A L I DD SS C input capacitance V =V - - 7 pF i I SS I/Os; P0 to P7 V LOW-level input voltage 0.5 - +0.3V V IL DD V HIGH-level input voltage 0.7V - V +0.5 V IH DD DD I maximum allowed input current V V or V V - - 400 A IHL(max) I DD I SS through protection diode I LOW-level output current V =1V; V =5V 10 25 - mA OL OL DD I HIGH-level output current V =V 30 - 300 A OH OH SS I transient boosted pull-up current HIGH during acknowledge (see - 1 - mA trt(pu) Figure8); V =V ; V =2.5V OH SS DD C input capacitance - - 10 pF i C output capacitance - - 10 pF o Interrupt INT (see Figure8) I LOW-level output current V =0.4V 1.6 - - mA OL OL I leakage current V =V or V 1 - +1 A L I DD SS Select inputs A0, A1, A2 V LOW-level input voltage 0.5 - +0.3V V IL DD V HIGH-level input voltage 0.7V - V +0.5 V IH DD DD I input leakage current pin at V or V 250 - +250 nA LI DD SS [1] The power-on reset circuit resets the I2C-bus logic at V <V and sets all I/Os to logic1 (with current source to V ). DD POR DD PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 16 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt 14. Dynamic characteristics Table 10. Dynamic cha racteristics V =2.5V to 6V; V =0V; T =40C to +85C; unless otherwise specified. DD SS amb Symbol Parameter Conditions Min Typ Max Unit I2C-bus timing[1] (see Figure17) f SCL clock frequency - - 100 kHz SCL t bus free time between a STOP and 4.7 - - s BUF STARTcondition t hold time (repeated) START condition 4 - - s HD;STA t set-up time for a repeated START condition 4.7 - - s SU;STA t set-up time for STOP condition 4 - - s SU;STO t data hold time 0 - - ns HD;DAT t data valid time - - 3.4 s VD;DAT t data set-up time 250 - - ns SU;DAT t LOW period of the SCL clock 4.7 - - s LOW t HIGH period of the SCL clock 4 - - s HIGH t rise time of both SDA and SCL signals - - 1 s r t fall time of both SDA and SCL signals - - 0.3 s f Port timing (see Figure8 and Figure9) t data output valid time C 100pF - - 4 s v(Q) L t data input set-up time C 100pF 0 - - s su(D) L t data input hold time C 100pF 4 - - s h(D) L Interrupt INT timing (see Figure9) t valid time on pin INT from port to INT; - - 4 s v(INT) C 100pF L t reset time on pin INT from SCL to INT; - - 4 s rst(INT) C 100pF L [1] All the timing values are valid within the operating supply voltage and ambient temperature range and refer to V and V with an input IL IH voltage swing of VSS to VDD. PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 17 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt START bit 7 STOP bit 6 bit 0 acknowledge protocol condition MSB condition (A6) (R/W) (A) (S) (A7) (P) tSU;STA tLOW tHIGH 1 / fSCL SCL 0.7 × VDD 0.3 × VDD tBUF tf tr SDA 0.7 × VDD 0.3 × VDD tHD;STA tSU;DAT tHD;DAT tVD;DAT tVD;ACK tSU;STO 002aab175 Rise and fall times refer to V and V . IL IH Fig 17. I2C-bus timing diagram PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 18 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt 15. Package outline DIP16: plastic dual in-line package; 16 leads (300 mil) SOT38-4 D ME e n a pl g n eati A2 A s L A1 c Z e w M b1 (e ) 1 b b2 16 9 MH pin 1 index E 1 8 0 5 10 mm scale DIMENSIONS (inch dimensions are derived from the original mm dimensions) UNIT mAax. mAi n1 . mAa 2x . b b1 b2 c D(1) E(1) e e1 L ME MH w mZa(1x). 1.73 0.53 1.25 0.36 19.50 6.48 3.60 8.25 10.0 mm 4.2 0.51 3.2 2.54 7.62 0.254 0.76 1.30 0.38 0.85 0.23 18.55 6.20 3.05 7.80 8.3 inches 0.17 0.02 0.13 0.068 0.021 0.049 0.014 0.77 0.26 0.1 0.3 0.14 0.32 0.39 0.01 0.03 0.051 0.015 0.033 0.009 0.73 0.24 0.12 0.31 0.33 Note 1. Plastic or metal protrusions of 0.25 mm (0.01 inch) maximum per side are not included. OUTLINE REFERENCES EUROPEAN ISSUE DATE VERSION IEC JEDEC JEITA PROJECTION 95-01-14 SOT38-4 03-02-13 Fig 18. Package outline SOT38-4 (DIP16) PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 19 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt SO16: plastic small outline package; 16 leads; body width 7.5 mm SOT162-1 D E A X c y HE v M A Z 16 9 Q A2 A A1 (A 3 ) pin 1 index θ Lp L 1 8 detail X e w M bp 0 5 10 mm scale DIMENSIONS (inch dimensions are derived from the original mm dimensions) UNIT mAax. A1 A2 A3 bp c D(1) E(1) e HE L Lp Q v w y Z(1) θ 0.3 2.45 0.49 0.32 10.5 7.6 10.65 1.1 1.1 0.9 mm 2.65 0.25 1.27 1.4 0.25 0.25 0.1 0.1 2.25 0.36 0.23 10.1 7.4 10.00 0.4 1.0 0.4 8o 0.012 0.096 0.019 0.013 0.41 0.30 0.419 0.043 0.043 0.035 0o inches 0.1 0.01 0.05 0.055 0.01 0.01 0.004 0.004 0.089 0.014 0.009 0.40 0.29 0.394 0.016 0.039 0.016 Note 1. Plastic or metal protrusions of 0.15 mm (0.006 inch) maximum per side are not included. OUTLINE REFERENCES EUROPEAN ISSUE DATE VERSION IEC JEDEC JEITA PROJECTION 99-12-27 SOT162-1 075E03 MS-013 03-02-19 Fig 19. Package outline SOT162-1 (SO16) PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 20 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt SSOP20: plastic shrink small outline package; 20 leads; body width 4.4 mm SOT266-1 D E A X c y HE v M A Z 20 11 Q pin 1 index A2 A1 (A 3 ) A θ Lp L 1 10 detail X w M e bp 0 2.5 5 mm scale DIMENSIONS (mm are the original dimensions) UNIT mAax. A1 A2 A3 bp c D(1) E(1) e HE L Lp Q v w y Z(1) θ mm 1.5 0.015 11..42 0.25 00..3220 00..2103 66..64 44..53 0.65 66..62 1 00..7455 00..6455 0.2 0.13 0.1 00..4188 100oo Note 1. Plastic or metal protrusions of 0.20 mm maximum per side are not included. OUTLINE REFERENCES EUROPEAN ISSUE DATE VERSION IEC JEDEC JEITA PROJECTION 99-12-27 SOT266-1 MO-152 03-02-19 Fig 20. Package outline SOT266-1 (SSOP20) PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 21 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt 16. Handling information All input and output pins are protected against ElectroStatic Discharge (ESD) under normal handling. When handling ensure that the appropriate precautions are taken as described in JESD625-A or equivalent standards. 17. Soldering of SMD packages This text provides a very brief insight into a complex technology. A more in-depth account of soldering ICs can be found in Application Note AN10365 “Surface mount reflow soldering description”. 17.1 Introduction to soldering Soldering is one of the most common methods through which packages are attached to Printed Circuit Boards (PCBs), to form electrical circuits. The soldered joint provides both the mechanical and the electrical connection. There is no single soldering method that is ideal for all IC packages. Wave soldering is often preferred when through-hole and Surface Mount Devices (SMDs) are mixed on one printed wiring board; however, it is not suitable for fine pitch SMDs. Reflow soldering is ideal for the small pitches and high densities that come with increased miniaturization. 17.2 Wave and reflow soldering Wave soldering is a joining technology in which the joints are made by solder coming from a standing wave of liquid solder. The wave soldering process is suitable for the following: • Through-hole components • Leaded or leadless SMDs, which are glued to the surface of the printed circuit board Not all SMDs can be wave soldered. Packages with solder balls, and some leadless packages which have solder lands underneath the body, cannot be wave soldered. Also, leaded SMDs with leads having a pitch smaller than ~0.6mm cannot be wave soldered, due to an increased probability of bridging. The reflow soldering process involves applying solder paste to a board, followed by component placement and exposure to a temperature profile. Leaded packages, packages with solder balls, and leadless packages are all reflow solderable. Key characteristics in both wave and reflow soldering are: • Board specifications, including the board finish, solder masks and vias • Package footprints, including solder thieves and orientation • The moisture sensitivity level of the packages • Package placement • Inspection and repair • Lead-free soldering versus SnPb soldering 17.3 Wave soldering Key characteristics in wave soldering are: PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 22 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt • Process issues, such as application of adhesive and flux, clinching of leads, board transport, the solder wave parameters, and the time during which components are exposed to the wave • Solder bath specifications, including temperature and impurities 17.4 Reflow soldering Key characteristics in reflow soldering are: • Lead-free versus SnPb soldering; note that a lead-free reflow process usually leads to higher minimum peak temperatures (see Figure21) than a SnPb process, thus reducing the process window • Solder paste printing issues including smearing, release, and adjusting the process window for a mix of large and small components on one board • Reflow temperature profile; this profile includes preheat, reflow (in which the board is heated to the peak temperature) and cooling down. It is imperative that the peak temperature is high enough for the solder to make reliable solder joints (a solder paste characteristic). In addition, the peak temperature must be low enough that the packages and/or boards are not damaged. The peak temperature of the package depends on package thickness and volume and is classified in accordance with Table11 and12 Table 11. SnPb eutectic process (from J-STD-020D) Package thickness (mm) Package reflow temperature (C) Volume (mm3) < 350  350 < 2.5 235 220  2.5 220 220 Table 12. Lead-free process (from J-STD-020D) Package thickness (mm) Package reflow temperature (C) Volume (mm3) < 350 350 to 2000 > 2000 < 1.6 260 260 260 1.6 to 2.5 260 250 245 > 2.5 250 245 245 Moisture sensitivity precautions, as indicated on the packing, must be respected at all times. Studies have shown that small packages reach higher temperatures during reflow soldering, see Figure21. PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 23 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt maximum peak temperature = MSL limit, damage level temperature minimum peak temperature = minimum soldering temperature peak temperature time 001aac844 MSL: Moisture Sensitivity Level Fig 21. Temperature profiles for large and small components For further information on temperature profiles, refer to Application Note AN10365 “Surface mount reflow soldering description”. 18. Soldering of through-hole mount packages 18.1 Introduction to soldering through-hole mount packages This text gives a very brief insight into wave, dip and manual soldering. Wave soldering is the preferred method for mounting of through-hole mount IC packages on a printed-circuit board. 18.2 Soldering by dipping or by solder wave Driven by legislation and environmental forces the worldwide use of lead-free solder pastes is increasing. Typical dwell time of the leads in the wave ranges from 3secondsto4seconds at 250C or 265C, depending on solder material applied, SnPb or Pb-free respectively. The total contact time of successive solder waves must not exceed 5seconds. The device may be mounted up to the seating plane, but the temperature of the plastic body must not exceed the specified maximum storage temperature (T ). If the stg(max) printed-circuit board has been pre-heated, forced cooling may be necessary immediately after soldering to keep the temperature within the permissible limit. 18.3 Manual soldering Apply the soldering iron (24V or less) to the lead(s) of the package, either below the seating plane or not more than 2mm above it. If the temperature of the soldering iron bit is less than 300C it may remain in contact for up to 10seconds. If the bit temperature is between 300Cand400C, contact may be up to 5seconds. PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 24 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt 18.4 Package related soldering information Table 13. Suitability of through-hole mount IC packages for dipping and wave soldering Package Soldering method Dipping Wave CPGA, HCPGA - suitable DBS, DIP, HDIP, RDBS, SDIP, SIL suitable suitable[1] PMFP[2] - not suitable [1] For SDIP packages, the longitudinal axis must be parallel to the transport direction of the printed-circuit board. [2] For PMFP packages hot bar soldering or manual soldering is suitable. PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 25 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt 19. Soldering: PCB footprints Footprint information for reflow soldering of SO16 package SOT162-1 Hx Gx P2 (0.125) (0.125) Hy Gy By Ay C D2 (4x) P1 D1 Generic footprint pattern Refer to the package outline drawing for actual layout solder land occupied area DIMENSIONS in mm P1 P2 Ay By C D1 D2 Gx Gy Hx Hy 1.270 1.320 11.200 6.400 2.400 0.700 0.800 10.040 8.600 11.900 11.450 sot162-1_fr Fig 22. PCB footprint for SOT162-1 (SO16); reflow soldering PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 26 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt Footprint information for reflow soldering of SSOP20 package SOT266-1 Hx Gx P2 (0.125) (0.125) Hy Gy By Ay C D2 (4x) P1 D1 solder land occupied area DIMENSIONS in mm P1 P2 Ay By C D1 D2 Gx Gy Hx Hy 0.650 0.750 7.200 4.500 1.350 0.400 0.600 6.900 5.300 7.300 7.450 sot266-1_fr Fig 23. PCB footprint for SOT266-1 (SSOP20); reflow soldering PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 27 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt 20. Abbreviations Table 14. Abbreviations Acronym Description CDM Charged-Device Model CMOS Complementary Metal Oxide Semiconductor I/O Input/Output I2C-bus Inter IC bus ESD ElectroStatic Discharge FF Flip-Flop GPIO General Purpose Input/Output HBM Human Body Model IC Integrated Circuit LED Light Emitting Diode LP Low-Pass PLC Programmable Logic Controller POR Power-On Reset PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 28 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt 21. Revision history Table 15. Revision history Document ID Release date Data sheet status Change notice Supersedes PCF8574_PCF8574A v.5 20130527 Product data sheet - PCF8574 v.4 Modifications: • The format of this data sheet has been redesigned to comply with the new identity guidelines of NXP Semiconductors. • Legal texts have been adapted to the new company name where appropriate. • Electrical parameter letter-symbols and their definitions are updated to conform to NXP presentation standards. • Section 1 “General description”: updated • Section 2 “Features and benefits”: – third bullet item: appended “with non-overvoltage tolerant I/O held to V with 100A DD current source” – added (new) fourth and seventh bullet items – added sixth bullet item: “Total package sink capability of 80mA” – ninth bullet changed from “(10A maximum)” to “(2.5A typical)” – deleted (old) 11th, 12th and 13th bullet items • Added (new) eighth bullet item “Mobile devices” • Table 1 “Ordering information”: – Type number corrected from “PCF8574T” to “PCF8574/3” – Type number corrected from “PCF8574AT” to “PCF8574AT/3” – Type number corrected from “PCF8574TS” to “PCF8574TS/3” – Type number corrected from “PCF8574ATS” to “PCF8574ATS/3” • Added Section 4.1 “Ordering options” • Figure 4 “Pin configuration for SO16”: updated type numbers (appended “/3”) • Figure 5 “Pin configuration for SSOP20”: updated type numbers (appended “/3”) • Section 6.2 “Pin description”: combined DIP16, SO16 and SSOP20 pin descriptions into one table (Table3) • Section 7 “Functional description” reorganized • Section 7.1 “Device address”, first paragraph, fourth sentence: appended “so they must be externally held HIGH or LOW” • Table 4 “PCF8574 address map” updated: added column for 7-bit hexadecimal address without R/W • Table 5 “PCF8574A address map” updated: added column for 7-bit hexadecimal address without R/W • Section 8.1 “Quasi-bidirectional I/Os”: re-written and placed before Section 8.4 “Power-on reset” • added Section 8.2 “Writing to the port (Output mode)” • added Section 8.3 “Reading from a port (Input mode)” • Figure 9 “Read mode (input)”: changed symbol “t ” to “t ” ps su • Section 8.4 “Power-on reset” re-written • Section 8.5 “Interrupt output (INT)” re-written • Figure 10 “Application of multiple PCF8574/74As with interrupt” updated: changed device16 from “PCF8574” to “PCF8574A” • Section 9.3 “Acknowledge”, first paragraph, third sentence re-written. • Added Section 10 “Application design-in information” PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 29 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt Table 15. Revision history …continued Document ID Release date Data sheet status Change notice Supersedes Modifications: (continued) • Table 7 “Limiting values”: – changed parameter description for symbol I from “DC input current” to “input current” I – changed parameter description for symbol I from “DC output current” to “output O current” – changed parameter description for symbol I from “supply current” to “ground supply SS current” – changed symbol “P ” to “P/out” O – added T limits j(max) • Added Section 12 “Thermal characteristics” • Table 9 “Static characteristics”: – table title changed from “DC characteristics” to “Static characteristics” – sub-section “I/Os; P0 to P7”: changed parameter description for symbol I trt(pu) from “transient pull-up current” to “transient boosted pull-up current” – moved sub-section “Port timing” to Table 10 “Dynamic characteristics” – sub-section “Interrupt INT”: moved sub-sub-section “Timing” to Table 10 “Dynamic characteristics” • Table 10 “Dynamic characteristics”: – sub-section “I2C-bus timing”: deleted symbol/parameter “t , tolerable spike width on SW bus” – sub-section “Port timing”: changed symbol/parameter from “t , output data valid time” pv to“t , data output valid time” v(Q) – sub-section “Port timing”: changed symbol/parameter from “t , input data set-up time” su to“t , data input set-up time” su(D) – sub-section “Port timing”: changed symbol/parameter from “t , input data hold time” h to“t , data input hold time” h(D) – sub-section “Interrupt INT”: changed parameter description for symbol t v(INT) from “INT output valid time” to “valid time on pin INT” – sub-section “Interrupt INT”: changed parameter description for symbol t rst(INT) from “INT reset delay time” to “reset time on pin INT” • Added Section 19 “Soldering: PCB footprints” PCF8574 v.4 20021122 Product specification - PCF8574 v.3 (939775010462) PCF8574 v.3 20020729 Product specification - PCF8574 v.2 (939775009911) PCF8574 v.2 19970402 Product specification - PCF8574_PCF8574A v.1 (939775001758) PCF8574_PCF8574A v.1 199409 Product specification - - (939775070011) PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 30 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt 22. Legal information 22.1 Data sheet status Document status[1][2] Product status[3] Definition Objective [short] data sheet Development This document contains data from the objective specification for product development. Preliminary [short] data sheet Qualification This document contains data from the preliminary specification. Product [short] data sheet Production This document contains the product specification. [1] Please consult the most recently issued document before initiating or completing a design. [2] The term ‘short data sheet’ is explained in section “Definitions”. [3] The product status of device(s) described in this document may have changed since this document was published and may differ in case of multiple devices. The latest product status information is available on the Internet at URLhttp://www.nxp.com. 22.2 Definitions Suitability for use — NXP Semiconductors products are not designed, authorized or warranted to be suitable for use in life support, life-critical or safety-critical systems or equipment, nor in applications where failure or Draft — The document is a draft version only. The content is still under malfunction of an NXP Semiconductors product can reasonably be expected internal review and subject to formal approval, which may result in to result in personal injury, death or severe property or environmental modifications or additions. NXP Semiconductors does not give any damage. NXP Semiconductors and its suppliers accept no liability for representations or warranties as to the accuracy or completeness of inclusion and/or use of NXP Semiconductors products in such equipment or information included herein and shall have no liability for the consequences of applications and therefore such inclusion and/or use is at the customer’s own use of such information. risk. Short data sheet — A short data sheet is an extract from a full data sheet Applications — Applications that are described herein for any of these with the same product type number(s) and title. A short data sheet is intended products are for illustrative purposes only. NXP Semiconductors makes no for quick reference only and should not be relied upon to contain detailed and representation or warranty that such applications will be suitable for the full information. For detailed and full information see the relevant full data specified use without further testing or modification. sheet, which is available on request via the local NXP Semiconductors sales office. In case of any inconsistency or conflict with the short data sheet, the Customers are responsible for the design and operation of their applications full data sheet shall prevail. and products using NXP Semiconductors products, and NXP Semiconductors accepts no liability for any assistance with applications or customer product Product specification — The information and data provided in a Product design. It is customer’s sole responsibility to determine whether the NXP data sheet shall define the specification of the product as agreed between Semiconductors product is suitable and fit for the customer’s applications and NXP Semiconductors and its customer, unless NXP Semiconductors and products planned, as well as for the planned application and use of customer have explicitly agreed otherwise in writing. In no event however, customer’s third party customer(s). Customers should provide appropriate shall an agreement be valid in which the NXP Semiconductors product is design and operating safeguards to minimize the risks associated with their deemed to offer functions and qualities beyond those described in the applications and products. Product data sheet. NXP Semiconductors does not accept any liability related to any default, damage, costs or problem which is based on any weakness or default in the 22.3 Disclaimers customer’s applications or products, or the application or use by customer’s third party customer(s). Customer is responsible for doing all necessary testing for the customer’s applications and products using NXP Limited warranty and liability — Information in this document is believed to Semiconductors products in order to avoid a default of the applications and be accurate and reliable. However, NXP Semiconductors does not give any the products or of the application or use by customer’s third party representations or warranties, expressed or implied, as to the accuracy or customer(s). NXP does not accept any liability in this respect. completeness of such information and shall have no liability for the consequences of use of such information. NXP Semiconductors takes no Limiting values — Stress above one or more limiting values (as defined in responsibility for the content in this document if provided by an information the Absolute Maximum Ratings System of IEC60134) will cause permanent source outside of NXP Semiconductors. damage to the device. Limiting values are stress ratings only and (proper) operation of the device at these or any other conditions above those given in In no event shall NXP Semiconductors be liable for any indirect, incidental, the Recommended operating conditions section (if present) or the punitive, special or consequential damages (including - without limitation - lost Characteristics sections of this document is not warranted. Constant or profits, lost savings, business interruption, costs related to the removal or repeated exposure to limiting values will permanently and irreversibly affect replacement of any products or rework charges) whether or not such the quality and reliability of the device. damages are based on tort (including negligence), warranty, breach of contract or any other legal theory. Terms and conditions of commercial sale — NXP Semiconductors products are sold subject to the general terms and conditions of commercial Notwithstanding any damages that customer might incur for any reason whatsoever, NXP Semiconductors’ aggregate and cumulative liability towards sale, as published at http://www.nxp.com/profile/terms, unless otherwise customer for the products described herein shall be limited in accordance agreed in a valid written individual agreement. In case an individual with the Terms and conditions of commercial sale of NXP Semiconductors. agreement is concluded only the terms and conditions of the respective agreement shall apply. NXP Semiconductors hereby expressly objects to Right to make changes — NXP Semiconductors reserves the right to make applying the customer’s general terms and conditions with regard to the changes to information published in this document, including without purchase of NXP Semiconductors products by customer. limitation specifications and product descriptions, at any time and without notice. This document supersedes and replaces all information supplied prior No offer to sell or license — Nothing in this document may be interpreted or to the publication hereof. construed as an offer to sell products that is open for acceptance or the grant, conveyance or implication of any license under any copyrights, patents or other industrial or intellectual property rights. PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 31 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt Export control — This document as well as the item(s) described herein own risk, and (c) customer fully indemnifies NXP Semiconductors for any may be subject to export control regulations. Export might require a prior liability, damages or failed product claims resulting from customer design and authorization from competent authorities. use of the product for automotive applications beyond NXP Semiconductors’ standard warranty and NXP Semiconductors’ product specifications. Non-automotive qualified products — Unless this data sheet expressly states that this specific NXP Semiconductors product is automotive qualified, Translations — A non-English (translated) version of a document is for the product is not suitable for automotive use. It is neither qualified nor tested reference only. The English version shall prevail in case of any discrepancy in accordance with automotive testing or application requirements. NXP between the translated and English versions. Semiconductors accepts no liability for inclusion and/or use of non-automotive qualified products in automotive equipment or applications. 22.4 Trademarks In the event that customer uses the product for design-in and use in automotive applications to automotive specifications and standards, customer Notice: All referenced brands, product names, service names and trademarks (a) shall use the product without NXP Semiconductors’ warranty of the are the property of their respective owners. product for such automotive applications, use and specifications, and (b) whenever customer uses the product for automotive applications beyond I2C-bus — logo is a trademark of NXP B.V. NXP Semiconductors’ specifications such use shall be solely at customer’s 23. Contact information For more information, please visit: http://www.nxp.com For sales office addresses, please send an email to: salesaddresses@nxp.com PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 5 — 27 May 2013 32 of 33

PCF8574; PCF8574A NXP Semiconductors Remote 8-bit I/O expander for I2C-bus with interrupt 24. Contents 1 General description. . . . . . . . . . . . . . . . . . . . . . 1 18.3 Manual soldering . . . . . . . . . . . . . . . . . . . . . . 24 2 Features and benefits . . . . . . . . . . . . . . . . . . . . 1 18.4 Package related soldering information. . . . . . 25 3 Applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 19 Soldering: PCB footprints . . . . . . . . . . . . . . . 26 4 Ordering information. . . . . . . . . . . . . . . . . . . . . 2 20 Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . 28 4.1 Ordering options. . . . . . . . . . . . . . . . . . . . . . . . 2 21 Revision history . . . . . . . . . . . . . . . . . . . . . . . 29 5 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 3 22 Legal information . . . . . . . . . . . . . . . . . . . . . . 31 6 Pinning information. . . . . . . . . . . . . . . . . . . . . . 4 22.1 Data sheet status. . . . . . . . . . . . . . . . . . . . . . 31 6.1 Pinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 22.2 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 6.2 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . 4 22.3 Disclaimers . . . . . . . . . . . . . . . . . . . . . . . . . . 31 22.4 Trademarks . . . . . . . . . . . . . . . . . . . . . . . . . . 32 7 Functional description . . . . . . . . . . . . . . . . . . . 5 23 Contact information . . . . . . . . . . . . . . . . . . . . 32 7.1 Device address. . . . . . . . . . . . . . . . . . . . . . . . . 5 7.1.1 Address maps. . . . . . . . . . . . . . . . . . . . . . . . . . 5 24 Contents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 8 I/O programming . . . . . . . . . . . . . . . . . . . . . . . . 6 8.1 Quasi-bidirectional I/Os . . . . . . . . . . . . . . . . . . 6 8.2 Writing to the port (Output mode). . . . . . . . . . . 8 8.3 Reading from a port (Input mode) . . . . . . . . . . 9 8.4 Power-on reset. . . . . . . . . . . . . . . . . . . . . . . . . 9 8.5 Interrupt output (INT) . . . . . . . . . . . . . . . . . . . 10 9 Characteristics of the I2C-bus . . . . . . . . . . . . 11 9.1 Bit transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 9.1.1 START and STOP conditions. . . . . . . . . . . . . 11 9.2 System configuration . . . . . . . . . . . . . . . . . . . 11 9.3 Acknowledge . . . . . . . . . . . . . . . . . . . . . . . . . 12 10 Application design-in information . . . . . . . . . 13 10.1 Bidirectional I/O expander applications . . . . . 13 10.2 How to read and write to I/O expander (example) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 10.3 High current-drive load applications. . . . . . . . 14 10.4 Migration path. . . . . . . . . . . . . . . . . . . . . . . . . 14 11 Limiting values. . . . . . . . . . . . . . . . . . . . . . . . . 15 12 Thermal characteristics . . . . . . . . . . . . . . . . . 15 13 Static characteristics. . . . . . . . . . . . . . . . . . . . 16 14 Dynamic characteristics. . . . . . . . . . . . . . . . . 17 15 Package outline. . . . . . . . . . . . . . . . . . . . . . . . 19 16 Handling information. . . . . . . . . . . . . . . . . . . . 22 17 Soldering of SMD packages . . . . . . . . . . . . . . 22 17.1 Introduction to soldering. . . . . . . . . . . . . . . . . 22 17.2 Wave and reflow soldering. . . . . . . . . . . . . . . 22 17.3 Wave soldering. . . . . . . . . . . . . . . . . . . . . . . . 22 17.4 Reflow soldering. . . . . . . . . . . . . . . . . . . . . . . 23 18 Soldering of through-hole mount packages. 24 18.1 Introduction to soldering through-hole mount packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 18.2 Soldering by dipping or by solder wave . . . . . 24 Please be aware that important notices concerning this document and the product(s) described herein, have been included in section ‘Legal information’. © NXP B.V. 2013. All rights reserved. For more information, please visit: http://www.nxp.com For sales office addresses, please send an email to: salesaddresses@nxp.com Date of release: 27 May 2013 Document identifier: PCF8574_PCF8574A

Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: N XP: PCF8574AP,112 PCF8574AT/3,512 PCF8574ATS/3,118 PCF8574AT/3,518 PCF8574P,112 PCF8574T/3,512 PCF8574TS/3,112 PCF8574TS/3,118 PCF8574T/3,518