PCF8574 Remote Expander: Features, Specifications, and Applications

This 8-bit input/output (I/O) expander for the two-line bidirectional bus (I2C) is designed for 2.5-V to 6-V VCC operation. The PCF8574 device provides general-purpose remote I/O expansion for most microcontroller families by way of the I 2C interface [serial clock (SCL), serial data (SDA)]. The device features an 8-bit quasi-bidirectional I/O port (P0–P7), including latched outputs with highcurrent drive capability for directly driving LEDs. Each quasi-bidirectional I/O can be used as an input or output without the use of a data-direction control signal. At power on, the I/Os are high. In this mode, only a current source to VCC is active.

• Low Standby-Current Consumption of 10 μA Max 

• I 2C to Parallel-Port Expander 

• Open-Drain Interrupt Output 

• Compatible With Most Microcontrollers 

• Latched Outputs With High-Current Drive Capability for Directly Driving LEDs 

• Latch-Up Performance Exceeds 100 mA Per JESD 78, Class II

Texas Instruments PCF8574PW technical specifications, attributes, parameters and parts with similar specifications to Texas Instruments PCF8574PW.

• Telecom Shelters: Filter Units 

• Servers 

• Routers (Telecom Switching Equipment) 

• Personal Computers 

• Personal Electronics 

• Industrial Automation 

• Products with GPIO-Limited Processors

(1) The SCL and SDA pins must be tied directly to VCC because if SCL and SDA are tied to an auxiliary power supply that could be powered on while VCC is powered off, then the supply current, ICC, will increase as a result. 

A. Device address is configured as 0100000 for this example. 

B. P0, P2, and P3 are configured as outputs. 

C. P1, P4, and P5 are configured as inputs. 

D. P6 and P7 are not used and must be configured as outputs.