PCA8574AD Datasheet PDF - NXP

The PCA8574AD is an 8-bit remote I/O Expander for I²C-bus with interrupt. It consists of eight quasi-bidirectional ports, 400kHz I²C-bus interface, three hardware address inputs and interrupt output operating between 2.3 and 5.5V. The quasi-bidirectional port can be independently assigned as an input to monitor interrupt status or keypads or as an output to activate indicator devices such as LEDs. The system master can read from the input port or write to the output port through a single register. The low current consumption of 4.5µA (typical, static) is great for mobile applications and the latched output ports have 25mA high current sink drive capability for directly driving LEDs. The three hardware address pins allow eight of each device to be on the same I²C-bus, so there can be up to 16 of this I/O expander together on the same I²C-bus, supporting up to 128 I/Os. The internal power-on reset (POR) initializes the I/Os as inputs with a weak internal pull-up 100µA current source.

● Latched outputs with 25mA sink capability for directly driving LEDs

● Active low open-drain interrupt output

● Eight programmable slave addresses using three address pins

● Latch-up testing is done to JEDEC standard JESD78 which exceeds 100mA