Datasheet

PCA9534A
SCPS141H –SEPTEMBER 2006–REVISED AUGUST 2013 www.ti.com
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 I
2
C 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 I
2
C address and allow up to eight
devices to share the same I
2
C bus or SMBus.
The PCA9534A is pin-to-pin and I
2
C 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.
The PCA9534A and PCA9534 are identical, except for their fixed I
2
C address. This allows for up to 16 of these
devices (8 of each) on the same I
2
C bus.
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