8-bit I/O expander for I2C and SMBus control buses
The NXP PCA6408AHKX is an 8-bit I/O expander that connects to a host controller via I2C or SMBus at clock rates up to 400 kHz. It provides eight push-pull GPIOs, each capable of sourcing 10 mA or sinking 25 mA, sufficient to drive LEDs or small relays directly without external buffers.
Housed in a 16-lead XFQFN package (1.8 mm × 2.6 mm body, 0.40 mm pitch).
Interrupt and power-on-reset features
Includes a dedicated interrupt output (INT) that asserts when any input changes state, eliminating the need for polling. The integrated power-on-reset (POR) ensures the I/O ports start in a known high-impedance state at power-up, preventing unintended glitches on downstream loads.