MAX7321 is a 8-channel input-output chip from Texas Instruments
The MAX7321 is a 2‑wire serial‑interfaced I2C port expander that provides eight open‑drain I/O ports with selectable internal pull‑ups and transition detection. Each port can function as a logic input or an open‑drain output, and the device includes over‑voltage protection up to +6 V. The expander supports hot insertion, standby mode, and a latched interrupt output (INT) that signals input changes.
The datasheet includes absolute maximum ratings, electrical characteristics, timing parameters, typical operating curves, pin descriptions, and package information for the 16‑pin QSOP and 16‑pin TQFN versions. It also provides a family comparison table and details on address selection, power‑up default states, and input pull‑up configuration.
| Operating Supply Voltage (V+) | 1.71 V to 5.5 V |
|---|---|
| I2C Serial Interface Frequency | 400 kHz |
| Open‑Drain Output Sink Current | 20 mA per port |
| Overvoltage Protection | +6 V |
| Standby Current (typ) | 0.6 pA |
| Operating Temperature Range | -40 °C to +125 °C |
| Package Types | 16‑pin QSOP, 16‑pin TQFN |
The MAX7321 supports an I2C serial interface up to 400 kHz.
The device provides eight open‑drain I/O ports.
The INT output is an open‑drain pin that alerts when any input port changes state.
It operates from a supply voltage of 1.71 V to 5.5 V.