16 I/O I2C expander in a 24-TSSOP footprint
The NXP PCA9675PW,118 is a 16-bit I2C GPIO expander in a 24-TSSOP package, designed to add digital I/O to a system over a two-wire bus. The 16 I/O are configured as push-pull outputs, each capable of sinking 25 mA or sourcing 100 µA, which is enough to drive LEDs, small relays, or logic-level inputs directly. The I2C interface runs at up to 1 MHz, supporting Fast-mode+ throughput for applications like keypad scanning or status-indicator banks.
Interrupt output and event-driven I/O
An interrupt output (INT) signals the host MCU when any input pin changes state, so the system does not have to poll the I2C bus continuously. This is useful in battery-powered or latency-sensitive designs where the MCU can sleep until a button press or sensor edge wakes it.