IC Port Expander with 8 Open-Drain I/Os

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).

Applications

* Cell Phones * Notebooks * SAN/NAS * Satellite Radio * Servers

* 400kHz I2C Serial Interface

* +1.71V to +5.5V Operating Voltage

* 8 Open-Drain I/O Ports Rated to 20mA Sink Current

* I/O Ports Are Overvoltage Protected to +6V

* Any Port Can Be a Logic Input or an Open-Drain Output

* Selectable I/O Port Power-Up Default Logic States

* Transient Changes Are Latched, Allowing Detection Between Read Operations

* active-low INT Output Alerts Change on Inputs

* AD0 and AD2 Inputs Select from 16 Slave Addresses

* Low 0.6µA (typ) Standby Current

* -40°C to +125°C Operating Temperature