PCF8574AP I2C 8BIT I/O Expansion IC

The PCF8574 8-bit I2C I/O Expander is a versatile integrated circuit designed to expand the input/output capabilities of microcontrollers and single-board computers. Based on the Philips/NXP PCF8574 chip, this I/O expander communicates via the popular I2C bus protocol, making it perfect for hobbyists, educators, and professionals who need additional GPIO pins without consuming precious microcontroller resources. Its simple interface and reliable performance make it ideal for applications ranging from LED matrix control to keypad scanning and sensor interfacing.

Key Features:

• I2C Interface: Simple two-wire serial communication requiring only SDA and SCL connections, plus power and ground.
• 8 Additional I/O Pins: Provides eight bidirectional input/output ports, expandable by connecting multiple devices on the same I2C bus.
• Addressable Design: Supports up to eight devices on a single I2C bus through hardware address selection, allowing for 64 additional I/O pins.
• Breadboard and PCB Compatible: Standard DIP-16 package with through-hole pins for easy prototyping and permanent installations.
• Low Power Consumption: Ideal for battery-powered projects and energy-efficient applications.
• Open-Drain Outputs: Each I/O pin features an open-drain output with weak internal pull-up, suitable for driving LEDs and interfacing with various logic levels.
• Interrupt Output: Provides an interrupt signal to alert the host microcontroller when input states change, reducing the need for constant polling.
• Wide Compatibility: Works seamlessly with Arduino, Raspberry Pi, ESP8266, ESP32, and other microcontroller platforms.
• Part Number: PCF8574 (also available as PCF8574A variant with different addressing range)
• Operating Voltage: 2.5V to 6V, compatible with both 3.3V and 5V logic systems
• I2C Bus Speed: Supports standard-mode (100 kHz) and fast-mode (400 kHz) operation
• Output Current: Maximum 25mA per I/O pin
• Operating Temperature Range: -40°C to +85°C for industrial applications
• Package: DIP-16 (Dual In-line Package) with 16 pins on 2.54mm pitch
• Pin Configuration: 8 I/O ports (P0-P7), VSS, VDD, SDA, SCL, INT, and 3 address pins (A0-A2)

Applications

• GPIO Expansion: Add extra input/output pins to microcontrollers with limited GPIO availability.
• LED Control: Drive LED matrices, seven-segment displays, and indicator panels efficiently.
• Keypad and Button Interfacing: Connect matrix keypads and multiple buttons without using excessive microcontroller pins.
• Sensor Networks: Interface multiple digital sensors and switches in IoT and home automation projects.
• Educational Projects: Teach I2C communication protocols and digital I/O concepts in electronics courses.

Why Choose the PCF8574 8-bit I2C I/O Expander? The PCF8574 offers a proven, reliable solution for expanding your microcontroller's capabilities with minimal wiring complexity. Its straightforward I2C interface, wide voltage compatibility, and extensive library support across popular platforms make it an excellent choice for both beginners learning digital electronics and experienced developers building sophisticated multi-device systems. With comprehensive documentation and a strong community backing, you'll have the support you need to integrate this versatile chip into your next project.