I²C/SMBus, 16-bit I/O port, interrupt, TSSOP-24

The PCA9555 is a 24-pin CMOS device that provides 16 bits of General Purpose
parallel Input/Output (GPIO) expansion for I²C-bus/SMBus applications and was developed to
enhance the NXP Semiconductors family of I²C-bus I/O expanders. The improvements
include higher drive capability, 5-V I/O tolerance, lower supply current, individual
configuration, and smaller packaging. I/O expanders provide a simple solution when
additional I/O is needed for ACPI power switches, sensors, push buttons, LEDs, fans etc.
The PCA9555 consists of two 8-bit configurations (input or output selection), input, output
and polarity inversion (active HIGH or active LOW operation) registers.

Main features