I²C Port Expander with 12 Push-Pull Outputs and 4 Open-Drain I/Os

The MAX7327, a 2-wire serial-interfaced peripheral, features 12 push-pull outputs and four configurable open-drain I/O ports with selectable internal pullups and transition detection. Ports are overvoltage protected to +6V, independent of supply voltage.

The four I/O ports configured as inputs are continuously monitored for state changes (transition detection). State changes are indicated by the open-drain, +6V-tolerant active-low INT output. The interrupt is latched, detecting transient changes. When the MAX7327 is subsequently accessed through the serial interface, any pending interrupt is cleared. The 12 push-pull and the four open-drain outputs are rated to sink 20mA, and are capable of driving LEDs. The active-low RST input clears the serial interface, terminating any I²C communication to or from the MAX7327.

The MAX7327 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 two ports.

The MAX7327 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 (see Table 1 in the full data sheet).

The MAX7327 is available in the 24-pin QSOP and TQFN packages, and is specified over the -40°C to +125°C automotive temperature range.

Applications

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

* 400kHz I²C Serial Interface

* +1.71V to +5.5V Operating Voltage

* 12 Push-Pull Output Ports, Rated at 20mA Sink Current

* 4 Open-Drain I/O Ports, Rated at 20mA Sink Current

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

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

* Transient Changes are Latched, Allowing Detection Between Read Operations

* Active-Low INT Output Alerts Changes on Inputs

* AD0 and AD2 Inputs Select from 16 Slave Addresses

* Low 0.6µA (typ) Standby Current

* -40°C to +125°C Temperature Range