# I2C port expansion module, PCF8574, cascade support, 2.5-6V

> I2C port expansion module based on the PCF8574/PCF8574T chip, offering 8 individually configurable bidirectional I/O channels. Operates at 2.5V-6V, communicates over I2C at up to 400kHz, with a maximum current of 100mA per pin. I2C address selectable via 3 switches (A0-A2), supports cascading up to 8 modules on the same bus. Dimensions: 36 x 16mm.

- Page: https://sigmanortec.ro/en/i2c-port-expansion-module-pcf8574-cascade-support-25-6v
- Price: 7.27 RON
- Availability: In stock; 1-2 zile
- Reference: 9691 · EAN: 5945286574935
- Category: Mechatronics and IoT > Sensors and Modules > Expansion Module
- Specifications: tension: AD; Supply Voltage: 2.5; Maximum Input Voltage: 6
- Package (shipping data): 0.006 kg
- Updated: 2026-09-14
- Shop: [Sigmanortec.ro](https://sigmanortec.ro/en/llms.txt)
- Prices: RON, VAT included; prices and stock as of 2026-10-22 01:33 (Europe/Bucharest)

## Description

Quickly expand the number of GPIO pins via I2C, ideal for Arduino and other resource-constrained boards. It offers 8 bidirectional inputs and outputs, operates at 2.5-6V and communicates up to 400kHz. The I2C address is easily selected via switches, and cascading support allows up to 8 modules to be connected to the same bus.
The PCF8574 module, compatible with Arduino and other development boards, is an I/O interface extender based on the I2C protocol, essential for projects that require an additional number of inputs/outputs. This module uses the PCF8574 chip, an I/O expander for the I2C bus. Being a device with cascading support, users can add more modules in series to further expand the number of inputs/outputs. It is ideal for projects involving microcontrollers with a limited number of GPIO pins or when a simpler management of I/O resources is needed.
The module has 3 switches for selecting the I2C address. Each switch represents 2 bits, so with 3 switches, we can have a maximum of 8 individual I2C addresses when we cascade them (2 to the power of 3), so there is a limit of 8 modules in the cascade.
The module has a test function: Pins P0-P7 are alternated between High and Low levels at regular intervals of 2 seconds.
Specifications:
Main chip: PCF8574/PCF8574T
Interface type: I2C
Number of I/O channels: 8-bit
Working voltage: 2.5V - 6V
Cascading support: Yes, it allows adding additional modules in series
I2C frequency: Up to 400kHz
I2C addresses: Selectable by pins, maximum 8 addresses, address 0x27 with all switches ON
Typical applications: Expanding GPIO capabilities for microcontrollers, I2C communications.
Dimensions: 36 x 16mm
I2C Addresses:
The addresses can be set via pins as follows:
Hex address
Switch A2
Switch A1
Switch A0
0x20
LOW
0x21
LOW
HIGH
0x22
LOW
HIGH
LOW
0x23
LOW
HIGH
0x24
HIGH
LOW
0x25
HIGH
LOW
HIGH
0x26
HIGH
LOW
0x27
HIGH