PCA9555PW,112
Overview
The PCA9555PW,112 is a 16-bit I/O expander designed for I2C-bus and SMBus applications, providing a remote GPIO solution via a serial interface. It features 16 individual I/O pins that default to inputs on power-up but can be configured as push-pull outputs with up to 50mA sourcing capability. The device includes an active-LOW interrupt output to notify the host controller of input state changes, reducing the need for continuous polling over the I2C bus.
Why Choose This Part
It offers high flexibility with a Polarity Inversion register and a wide supply voltage range of 2.3V to 5.5V. The low standby current of 250uA and integrated power-on reset make it suitable for power-sensitive applications. Additionally, the push-pull output stage eliminates the need for external pull-up resistors when driving CMOS logic or LEDs.
Applications
Key Specifications
Getting Started
To integrate the PCA9555, connect the SCL and SDA lines to your host controller with appropriate pull-up resistors and set the hardware address pins (A0, A1, A2). Software implementation involves writing to the Configuration register (0x06-0x07) to set pin direction before accessing the Input or Output Port registers. For rapid prototyping, many engineers use universal TSSOP-24 breakout boards to connect the chip to an Arduino or Raspberry Pi.
