Remote 8-bit I/O Expander for I²C-bus

PCA8574N Block Diagram

PCA8574N Block Diagram

PCA8574N is the remote 8-bit I/O expander for I²C-bus with interrupt. It provide general-purpose remote I/O expansion via the two-wire bidirectional I²C-bus (serial clock (SCL), serial data (SDA)). It consist of eight quasi-bidirectional ports, 400kHz I²C‑bus interface, three hardware address inputs and interrupt output operating between 2.3 V and 5.5 V. 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 4.5 μA (typical, static) is great for mobile applications and the latched output ports have 25 mA high current sink drive capability for directly driving LEDs.

Why Used

  • Operating supply voltage 2.3 V to 5.5 V with 5.5 V tolerant I/Os held to VDD with 100 μA current source
  • 400 kHz I²C‑bus interface (Fast-mode I²C‑bus)
  • I²C‑bus to parallel port expander
  • 8-bit remote I/O pins that default to inputs at power-up
  • Latched outputs with 25 mA sink capability for directly driving LEDs

Where Used

  • Instrumentation and Test Measurement
  • Servers
  • LED Signs and Displays
  • PLCs
  • Industrial Control

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