PCF8574 I2C I/O Expander Module – IO Expansion Board

Expand your microcontroller's GPIO capabilities with the PCF8574 I2C I/O Expander Module. This compact development board is built around the NXP PCF8574 chip, delivering 8 additional quasi-bidirectional I/O ports over a simple 2-wire I2C interface — ideal for Arduino, Raspberry Pi, ESP32, and other popular development platforms.

Key Features

I2C Interface: Communicates via standard SDA/SCL lines, minimizing pin usage on your host microcontroller
8 Expandable I/O Pins: Add digital input/output channels with minimal wiring
Configurable I2C Address: Up to 8 modules can share the same bus using onboard address-select jumpers
Wide Voltage Compatibility: Works with 3.3V and 5V logic systems
SMD Components: Compact surface-mount design for clean, reliable connections
Available in Two Colors: Blue PCF8574 and Black PCF8574
Customizable: Fully supports integration into custom PCB and prototype designs

What's Included

1× PCF8574 I2C I/O Expansion Board (SMD version)

Ideal Applications

Arduino / Raspberry Pi / ESP32 GPIO expansion
LED matrix and button matrix control
Sensor array management
Embedded systems prototyping and development
LCD backpack / I2C LCD adapters

Compatible With

This module is compatible with most I2C-capable microcontrollers and single-board computers, making it a go-to choice for hobbyists, engineers, and educators building embedded or IoT projects.

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Frequently Asked Questions

Q: What does the PCF8574 I2C I/O Expander Module do?

A: The PCF8574 I2C I/O Expander Module adds 8 additional digital input/output pins to your microcontroller over a 2-wire I2C bus (SDA + SCL). This allows you to control more devices — such as LEDs, buttons, relays, or sensors — without using up all the native GPIO pins on your Arduino, Raspberry Pi, or ESP32.

Q: How many PCF8574 modules can I connect to the same I2C bus?

A: Up to 8 PCF8574 modules can be connected to the same I2C bus simultaneously by configuring the onboard address-select pins (A0, A1, A2). Each module gets a unique I2C address, giving you up to 64 additional I/O pins from a single pair of SDA/SCL wires.

Q: Is the PCF8574 I/O Expander compatible with both 3.3V and 5V systems?

A: Yes, the PCF8574 expansion board supports both 3.3V and 5V logic levels, making it compatible with a wide range of development platforms including Arduino (5V), Raspberry Pi (3.3V), and ESP32 (3.3V).

Q: What is the difference between the blue and black PCF8574 versions?

A: Both versions offer identical electrical functionality — the difference is the PCB color (blue or black). Choose whichever best fits your project's aesthetics or helps you organize multiple boards in a complex build.

Production & Packaging Notice

To maintain high stock availability and fast shipping times, our items are sourced from multiple verified manufacturing facilities. While the core quality, materials, and product specifications remain identical, you may notice slight variations in the packaging design, manufacturing origin, or the wording of the printed instructions.