28 I/O lines over a 2-wire bus
The MAX7300AAX+T is a 28-port I²C GPIO expander from Analog Devices in a 36-SSOP package (7.50 mm width). It adds 28 push-pull I/O lines to a host microcontroller using only the SDA and SCL pins — critical when the MCU's own GPIO count is exhausted or the board layout cannot route more than a two-wire bus to a remote sensor cluster.
Each I/O can source 4.5 mA or sink 10 mA, which is enough to drive a logic input or a low-current LED indicator without a discrete buffer transistor. The 400 kHz I²C clock sets the bus update rate — scanning all 28 inputs at 400 kHz yields a per-port latency of roughly 70 µs, acceptable for switch-debounce and status polling but not for high-speed encoder capture.
Interrupt output and package fit
A dedicated interrupt output (INT) pulls low when any input changes state, allowing the host processor to sleep between events — a power-saving feature for battery-operated sensor nodes or handheld instruments. The 36-SSOP package (0.295-inch body width) is a medium-density SMD form factor; the 0.65 mm pin pitch requires a standard PCB fab process, but the 7.50 mm width may conflict with narrow board edges or dense component placement near the connector row.
It is ROHS3 compliant, meaning no restricted substances and no exemption expiry to track for EU or global compliance documentation.