I²C Port Expander with 8 Open-Drain I/Os

Active: In Production.

The MAX7321 2-wire serial-interfaced peripheral features eight open-drain I/O ports with selectable internal pullups and transition detection. Any port may be used as a logic input or an open-drain output. Ports are overvoltage protected to +6V independent of supply voltage.

All I/O ports configured as inputs are continuously monitored for state changes (transition detection). State changes are indicated by the open-drain, active-low INT output. The interrupt is latched, allowing detection of transient changes. When the MAX7321 is subsequently accessed through the serial interface, any pending interrupt is cleared.

The open-drain outputs are rated to sink 20mA and are capable of driving LEDs.

The +6V tolerant active-low RST input clears the serial interface, terminating any I²C communication to or from the MAX7321.

The MAX7321 uses two address inputs with four-level logic to allow 16 I²C slave addresses. The slave address also determines the power-up logic state for the I/O ports, and enables or disables internal 40kΩ pullups in groups of four ports.

The MAX7321 is one device in a family of pin-compatible port expanders with a choice of input ports, open-drain I/O ports, and push-pull output ports.

The MAX7321 is available in 16-pin QSOP and TQFN packages, and is specified over the automotive temperature range (-40°C to +125°C).

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