The CA6408 is a low-voltage 8-bit GPIO expander designed to provide flexible remote I/O expansion through the I²C or SMBus interface. It features input, output, configuration, and polarity inversion registers, allowing each pin to be individually controlled. At power-up, all I/O pins default to inputs with internal weak pull-ups, ensuring stable logic levels when no external signals are applied.

A key advantage of the CA6408 is its dual-supply architecture: VCCI defines the interface voltage level for SCL/SDA and supports bidirectional level translation, while VCCP powers the core circuits and port pins. This makes the device ideal for mixed-voltage environments. The open-drain interrupt output signals changes in input states, reducing the need for continuous polling by the host.

With up to 1 MHz I²C speed, low standby current, 5 V tolerant I/O, integrated power-on reset, latch capability for direct LED driving, and robust ESD protection, the CA6408 is well suited for servers, telecom systems, routers, automation devices, and MCU-based applications with limited GPIO resources.