PCA9539PW,118
Overview
The PCA9539PW is a 16-bit I2C and SMBus I/O expander designed to provide remote I/O expansion for microcontrollers via a two-wire bidirectional bus. It features an active LOW hardware reset input and an interrupt output to notify the host of input state changes without constant polling. The device operates across a wide voltage range of 2.3V to 5.5V and includes a polarity inversion register for flexible logic configuration.
Why Choose This Part
This expander offers a very low standby current of 1 uA and includes internal noise filters on the SCL and SDA lines to ensure robust communication in noisy environments. The inclusion of a dedicated RESET pin allows for independent hardware initialization without cycling system power, which is critical for high-availability systems.
Applications
Key Specifications
Getting Started
To integrate the PCA9539PW, connect the SCL and SDA pins to the host I2C bus with appropriate pull-up resistors and set the hardware address pins. Use standard I2C libraries available for platforms like Arduino or STM32 to write to the four pairs of internal registers: Input, Output, Polarity Inversion, and Configuration. Ensure the active-low RESET pin is tied HIGH for normal operation or connected to a system reset line.
