16-bit I²C I/O expander with push-pull outputs
The Maxim Integrated MAX7318AAG+ is a 16-bit I/O expander controlled via an I²C or SMBus interface, designed to add general-purpose digital I/O to a system without consuming extra MCU pins. Each of the 16 I/O lines can be configured independently as input or push-pull output, and the part includes a power-on reset (POR) feature that initializes the outputs to a known state after power-up. The 400 kHz clock frequency supports standard and fast-mode I²C buses, and the interrupt output (INT) signals the host when an input changes state, reducing polling overhead.
Output drive and package
Each output can source 31 mA or sink 43 mA, enough to drive an LED or a small relay coil directly without a transistor buffer. The part is surface-mount only.
For dual-sourcing or supply resilience, Maxim's own MAX7318 family includes the same 16-bit I²C expander in different package options; the AAG+ variant is the 24-SSOP version.