PCF8574 Module - 8-bit I/O Expander for I2C Bus

PCF8574A chip allows to have up to 8 digital inputs/outputs connected through I2C bus. Thanks to three address lines (which can be set to 0 or 1 via handy DIP switches), a single I2C bus can handle up to 8 such chips/modules. This means you are able to extend the number of Arduino I/O ports by 64.

PCF857 vs PCF8574A

Depending on batch we have modules with PCF8574 or PCF8574A. What is the difference? Basic I2C address - 0x27 or 0x3F. For use with own programs it does not matter, You just use proper address in Your program. If Your case needs specific chip - please contact us before You place an order.

In our offer you will find also PCF8574 and PCF8574A in DIP package.

Check out the examples of using this chip on our blog Starter Kit (not translated yet).

Specification:

• Supply voltage: 2,5 V - 6 V
• Power consumption: 100 µA during data transfer, 10 µA in stand-by
• Logic level: depends on supply voltage 3,3 V or 5 V
• Interface: I2C (TWI), adsresses from 0x38 to 0x3F
• Current output in LOW state: 25 mA
• Current output in HIGH state: 300 µA

Pinout:

• Vcc - supply voltage
• GND - ground
• SDA - I2C data line
• SDL - I2C clock line
• P0 .. P7 - digital I/O
• /INT - interrupt output
• A0 .. A2 - I2C address settings