CAT9554

CAT9554, CAT9554A 8-bit I2C and SMBus I/O Port with Interrupt Description The CAT9554 and CAT9554A are CMOS devices that provide 8−bit parallel input/output port expansion for I2C and SMBus compatible applications. These I/O expanders provide a simple solution in applications where additional I/Os are needed: sensors, power switches, LEDs, pushbuttons, and fans. The CAT9554/9554A consist of an input port register, an output port register, a configuration register, a polarity inversion register and an I2C/SMBus−compatible serial interface. Any of the eight I/Os can be configured as an input or output by writing to the configuration register. The system master can invert the CAT9554/9554A input data by writing to the active−high polarity inversion register. The CAT9554/9554A features an active low interrupt output which indicates to the system master that an input state has changed. The device’s extended addressing capability allows up to 8 devices to share the same bus. The CAT9554A is identical to the CAT9554 except the fixed part of the I2C slave address is different. This allows up to 16 of devices (eight CAT9554 and eight CAT9554A) to be connected on the same bus. Features 400 kHz I2C Bus Compatible (Note 1) 2.3 V to 5.5 V Operation Low Stand−by Current 5 V Tolerant I/Os 8 I/O Pins that Default to Inputs at Power−up High Drive Capability Individual I/O Configuration Polarity Inversion Register Active Low Interrupt Output Internal Power−on Reset No Gl...