TCA6424A 24-bit I/O Expander The Texas Instruments TCA6424A 24-bit I/O expander for I²C is designed to provide general-purpose remote I/O expansion for most microcontroller families via the I²C interface. The major benefit of the TI TCA6424A I/O expander is its wide Vcc range. The TCA6424A can operate from 1.65V to 5.5V on the P-port side and on the SDA/SCL side where supply levels are dropping down to conserve power. This TI I/O expander features low standby current consumption of 1µA.