NXP | PCA9554PW,112

NXP is a leading semiconductor company founded by Philips more than 50 years ago. NXP creates semiconductors, system solutions and software that deliver better sensory experiences in TVs, set-top boxes, identification applications, mobile phones, cars and a wide range of other electronic devices.

The PCA9554 and PCA9554A are 16-pin CMOS devices that provide 8 bits of General Purpose parallel Input/Output (GPIO) expansion for I2C-bus/SMBus applications and were developed to enhance the NXP Semiconductors family of I2C-bus I/O expanders. The improvements include higher drive capability, 5 V I/O tolerance, lower supply current, individual I/O configuration, 400 kHz clock frequency, and smaller packaging. I/O expanders provide a simple solution when additional I/O is needed for ACPI power switches, sensors, push buttons, LEDs, fans, etc.

The PCA9554/PCA9554A consist of an 8-bit Configuration register (Input or Output selection); 8-bit Input Port register, 8-bit Output Port register and an 8-bit Polarity Inversion register (active HIGH or active LOW operation). The system master can enable the I/Os as either inputs or outputs by writing to the I/O configuration bits. The data for each input or output is kept in the corresponding Input Port or Output Port register. The polarity of the read register can be inverted with the Polarity Inversion register. All registers can be read by the system master. Although pin-to-pin and I2C-bus address compatible with the PCF8574 series, some software changes are required due to the enhancements.

The PCA9554/PCA9554A open-drain interrupt output is activated when any input state differs from its corresponding Input Port register state and is used to indicate to the system master that an input state has changed. The power-on reset sets the registers to their default values and initializes the device state machine.

Three hardware pins (A0, A1, A2) vary the fixed I2C-bus address and allow up to eight devices to share the same I2C-bus/SMBus. The PCA9554A is identical to the PCA9554 except that the fixed I2C-bus address is different allowing up to sixteen of these devices (eight of each) on the same I2C-bus/SMBus.

The PCA9554PW is an I/O Expander with 8 I /O’s. It has a Frequency – Clock of 400kHz and a voltage – supply 2.3 V ~ 5.5 V. It is 16-pin and is packaged in TSSOP. The PCA9554PW is housed in a tube.