MAX7321

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 (see Table 1). The MAX7321 is available in 16-pin QSOP and TQFN packages, and is specified over the automotive temperature range (-40°C to +125°C). The open-drain outputs are rated to sink 20mA and are capable of driving LEDs. The 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 40k pullups in groups of four ports. 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 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 features of MAX7321 can be summarized as (1)400kHz I2C serial interface; (2)+1.71V to +5.5V operating voltage; (3)8 open-drain I/O ports rated to 20mA sink current; (4)I/O ports are overvoltage protected to +6V; (5)any port can be a logic input or an open-drain output; (6)selectable I/O port power-up default logic states; (7)transient changes are latched, allowing detection between read operations; (8)INT output alerts change on inputs; (9)AD0 and AD2 inputs select from 16 slave addresses; (10)low 0.6A (typ)standby current; (11)-40°C to +125°C operating temperature.

The absolute maximum ratings of MAX7321 are (1)supply voltage V+: -0.3V to +6V; (2)SCL, SDA, AD0, AD2, RST, INT, P0-P7: -0.3V to +6V; (3)P0-P7 sink current: 25mA; (4)SDA sink current: 10mA; (5)INT sink current: 10mA; (6)total V+ Current: 50mA; (7)total GND Current : 100mA; (8)continuous power dissipation (TA = +70°C)16-Pin QSOP (derate 8.3mW/°C above +70°C): 667mW/ 16-Pin TQFN (derate 15.6mW/°C above +70°C): 1250mW; (9)operating temperature range: -40°C to +125°C; (10)junction temperature: +150°C; (11)storage temperature range: -65°C to +150°C; (12)lead temperature (soldering, 10s): +300°C.