8 bit I/O expander

Maxim has introduced the MAX7310 general purpose I/O expander.

Packaged in 16 pin TSSOP, QSOP and QFN packages, the device interfaces the 2 wire, SMBus/I2C-compatible serial interface of microprocessor and microcontrollers to 8 I/O ports.

All ports power up as inputs but can be configured by the master as either an input or output.

Capable of sinking up to 30 mA, each I/O port has fixed logic thresholds compatible with 2.5, 3.3 and 5.5 V logic levels.

The first port is a 5 V tolerant, open-drain output for logic-level translation.

The expander has an input port register, an output port register, a configuration register, a bus timeout register and a polarity inversion register, all communicated through the 400 kHz two wire serial interface.

For lock-up-free operation the SMBus timeout function alerts the master when the bus times out; it can also be disabled in software.

Three address pins provide 56 slave IDs which connect as many devices on the same bus and avoid address conflicts with other system devices.

By pulling the reset pin, reset-bar, to the active-low position, the system master can reset the I/Os to inputs, and all registers and state machines to their default states.

The device operates from 2.3 to 5.5 V over the automotive temperature range (-40 to +125°C). The average supply current is 29 µA and standby current is 1.7 µA.