TI PCA9554PWR

I2C to Parallel Port Expander. This 8-bit I/O expander for the two-wire bidirectional bus (I2C) is designed to operate between 2.3V and 5.5V VCC. Through the I2C interface [Serial Clock (SCL), Serial Data (SDA)], it provides general-purpose remote I/O expansion for most microcontroller families. The PCA9554 contains an 8-bit configuration (input or output selectable), input, output, and polarity inversion (active-high or active-low) registers. Upon power-up, the I/Os are configured as weak pull-up inputs to VCC. However, the system master controller can enable the I/Os as inputs or outputs by writing to the I/O configuration bits. The data for each input or output is stored in the corresponding input or output register. The polarity of the input port register can be inverted using the polarity inversion register. All registers can be read by the system master. In the event of a timeout or other improper operation, the system master can reset the PCA9554 by using the power-on reset function to place the registers in their default state and initialize the I2C/SMBus state machine. The PCA9554 open-drain interrupt (INT) 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 the input state has changed. INT can be connected to the interrupt input of a microcontroller. By sending an interrupt signal on this line, the remote I/O can inform the microcontroller if there is incoming data on its ports without having to communicate via the I2C bus. Thus, the PCA9554 can remain a simple slave device. The device's outputs (latched) have high-current drive capability for directly driving LEDs and low current consumption. Three hardware pins (A0, A1, and A2) are used to program and vary the fixed I2C address and allow up to eight devices to share the same I2C bus or SMBus. The PCA9554 is pin-to-pin and I2C address compatible with the PCF8574. However, software changes are required due to the enhancements in the PCA9554 over the PCF8574. The PCA9554 and PCA9554A are identical except for their fixed I2C address. This allows for up to 16 of these devices (eight of each) on the same I2C/SMBus.

• Open-drain, active-low interrupt output
• 2.3V to 5.5V operating supply voltage range
• 5V-tolerant I/O
• 400kHz Fast-mode I2C bus
• 3 hardware address pins supporting up to 8 devices on I2C/SMBus
• Input/output configuration registers
• Polarity inversion registers
• Internal power-on reset
• All channels configured as inputs at power-on
• Glitch-free outputs at power-on
• Latched outputs with high-current drive capability for direct LED driving
• Latch-up performance exceeding 100mA, compliant with JESD 78 Class II
• ESD protection exceeding JESD 22 specifications
  • 2000V Human Body Model (A114-A)
  • 200V Machine Model (A115-A)
  • 1000V Charged Device Model (C101)