The PCA9535 and PCA9535C are 24-pin CMOS devices that provide 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 I/O 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.
