PCA9538D,112

The PCA9538D,112 from NXP Semiconductors is a 16-pin CMOS device designed to provide 8 bits of General Purpose parallel Input/Output (GPIO) expansion for I2C-bus/SMBus applications. This I/O expander is suitable for systems requiring additional I/O for components such as ACPI power switches, sensors, push-buttons, and LEDs.

Key features include an 8-bit Configuration register for input/output selection, an 8-bit Input Port register, an 8-bit Output Port register, and an 8-bit Polarity Inversion register. The device supports active HIGH or active LOW operation and can be configured by the system master. It operates with a supply voltage range of 2.3 V to 5.5 V and supports a clock frequency up to 400 kHz. The I/Os are 5 V tolerant.

The PCA9538D,112 includes an open-drain interrupt output that activates when an input state changes, signaling the system master. A power-on reset function initializes the device, and a dedicated RESET pin allows for reset without de-powering. Two hardware pins, A0 and A1, allow for address variation, enabling up to four devices on the same I2C-bus. The device is offered in a 16-SOIC package suitable for surface mounting.

This I/O expander is useful in applications needing to increase the number of available digital I/Os without significantly increasing system complexity or power consumption. Its integrated interrupt and reset features simplify system design and management.