TI PCA9534ADGVR

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 PCA9534A contains an 8-bit configuration (input or output selectable), an input port, an output port, and a polarity inversion (active-high or active-low) register. At power-up, the I/Os are configured as inputs. 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 case of a timeout or other improper operation, the system master can reset the PCA9534A by using the power-on reset function to place the registers in their default states and initialize the I2C/SMBus state machine. The PCA9534A 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 an input state has changed. The PCA9534A and PCA9534 are identical, except for their fixed I²C address. This allows for up to 16 of these devices (8 of each) on the same I²C bus. 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 PCA9534A can remain a simple slave device. The device's outputs (latched) have high-current drive capability for directly driving LEDs. It has 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 PCA9534A is pin-to-pin and I²C address compatible with the PCF8574A. However, software changes are required due to the enhancements in the PCA9534A over the PCF8574A. The PCA9534A is a low-power version of the PCA9554A. The only difference between the PCA9534A and PCA9554A is that the PCA9534A eliminates an internal I/O pullup resistor, which dramatically reduces power consumption in the standby mode when the I/Os are held low.

• 1μA low standby current consumption (maximum)
• I2C to parallel port expander
• Open-drain active-low interrupt output
• Operating supply voltage range: 2.3V to 5.5V
• 5V-tolerant I/O ports
• 400kHz fast-mode I2C bus
• Three hardware address pins allow up to eight devices on I2C/SMBus; up to 16 devices when used with PCA9534
• Input and output configuration registers
• Polarity inversion register
• Internal power-on reset
• All channels configured as inputs at power-up, no glitch at power-on
• Noise filters on SCL and SDA inputs
• Latched outputs with maximum high-current drive capability for direct LED driving
• Latch-up performance exceeds 100mA per JESD 78 Class II
• ESD protection exceeds JESD 22: 2000V Human Body Model (A114-A), 200V Machine Model (A115-A), 1000V Charged Device Model (C101)