I²C & SMBus I/O Expander: TCA6416A The Texas Instruments TCA6416A 16-bit I/O expander for the two-line bidirectional bus (I²C) is designed to provide general-purpose remote I/O expansion for most microcontroller families via the I²C interface. The TI TCA6416A provides a wide VCC range. It can operate from 1.65 V to 5.5 V on the P-port side and on the SDA/SCL side. This allows the TI TCA6416A I/O expander to interface with next-generation microprocessors and microcontrollers on the SDA/SCL side, where supply levels are dropping down to conserve power. One hardware pin (ADDR) can be used to program and vary the fixed I²C address and allow up to two devices to share the same I²C bus or SMBus.