PCA9554APW,118
Overview
The PCA9554APW is an 8-bit I/O expander designed for I2C-bus or SMBus applications, providing a simple solution for adding GPIO to a system via a 2-wire serial interface. It features a push-pull output stage, an active-low interrupt output to notify the host of input state changes, and a Polarity Inversion register for flexible software control. Operating from 2.3V to 5.5V, it is well-suited for low-power systems requiring extra digital control pins with minimal trace routing.
Why Choose This Part
The device includes a built-in power-on reset that initializes all 8 I/Os as inputs, preventing unintended output states during startup. Its active-low interrupt output eliminates the need for the MCU to constantly poll the expander for input changes, significantly reducing bus traffic and power consumption. Additionally, internal noise filters on SCL and SDA lines ensure robust communication in electrically noisy environments.
Applications
Key Specifications
Getting Started
To interface with the PCA9554APW, connect the SCL and SDA lines to your microcontroller's I2C master peripheral with appropriate pull-up resistors. Set the hardware address using the three address pins (A0, A1, A2) to avoid conflicts with other I2C devices. Software implementation involves writing to four internal registers: Input port, Output port, Polarity Inversion, and Configuration.
