PCF8574 Application Note

●The PCF8574T/3,518 is a 8-bit remote I/O Expander for I²C-bus with interrupt. It provides general-purpose remote I/O expansion via the two-wire bidirectional I²C-bus (serial clock (SCL), serial data (SDA)). The devices consist of eight quasi-bidirectional ports, 100kHz I²C-bus interface, three hardware address inputs and interrupt output operating between 2.5 and 6V. 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. System master can read from the input port or write to the output port through a single register. The low current consumption of 2.5µA (typical, static) is great for mobile applications and the latched output ports directly drive LEDs. This is identical, except for the different fixed portion of the slave address.

● I²C-bus to parallel port expander

● 100kHz I²C-bus Interface (standard-mode I²C-bus)

● Latched outputs directly drive LEDs

● Total package sink capability of 80mA

● Active low open-drain interrupt output

● 2.5µA Typical low standby current

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

● -40 to +85°C Operating temperature range

●ESD sensitive device, take proper precaution while handling the device.