I²C port expander with 4 GPIOs and interrupt
The Maxim Integrated MAX7322ATE+ is a 4-bit I²C port expander in a 16-TQFN (3x3) package with exposed pad. It adds four general-purpose I/O pins to a host controller over a 400 kHz I²C bus, with each I/O capable of sourcing or sinking 20 mA. The part includes a Power-On Reset (POR) feature that forces all outputs to a known state at power-up, and an interrupt output that signals the host when an input changes state, eliminating the need for continuous bus polling.
The supply voltage range of 1.7V to 5.5V covers both 1.8V and 3.3V logic families as well as 5V legacy systems, making this a flexible fit for mixed-voltage designs.
The pad is electrically connected to ground, so the PCB ground plane serves as the heatsink. Surface-mount assembly is standard; no special reflow profile beyond the usual lead-free process is needed.