PCF8574T/3
I2C interface remote I/O expander with 8 channels in 16-pin SOIC package
Manufacturer： nxp
series introduction
# Introduction to the PCF8574T/3 Product Series
## 1. Overview
The PCF8574T/3 is a highly versatile and widely - used integrated circuit belonging to the family of I/O expanders. It is designed to provide an efficient solution for expanding the input - output (I/O) capabilities of microcontrollers and other digital systems. This product series is manufactured by well - known semiconductor companies and is known for its reliability, ease of use, and cost - effectiveness.
## 2. Key Features
### 2.1 I/O Expansion
- The PCF8574T/3 offers 8 - bit bidirectional I/O ports. This means that it can be used to add up to 8 additional input or output pins to a system. For example, if a microcontroller has limited I/O pins and needs to interface with multiple sensors or actuators, the PCF8574T/3 can be used to bridge the gap.
- Each I/O pin can be individually configured as an input or an output, providing great flexibility in system design.
### 2.2 I2C Interface
- It communicates with the host device (such as a microcontroller) using the Inter - Integrated Circuit (I2C) bus protocol. The I2C bus is a widely adopted serial communication protocol that requires only two wires (SDA - Serial Data Line and SCL - Serial Clock Line) for communication.
- This simplifies the wiring and reduces the overall complexity of the system. The I2C interface also allows multiple PCF8574T/3 devices to be connected to the same bus, enabling further expansion of I/O capabilities. The device has a programmable I2C address, which can be set using three address pins (A0, A1, A2), allowing up to 8 different devices to be connected on the same I2C bus.
### 2.3 Low Power Consumption
- The PCF8574T/3 is designed to operate with low power consumption, making it suitable for battery - powered applications. It has a low standby current, which helps to extend the battery life of portable devices.
- This low - power operation also reduces the heat generated by the device, improving the overall reliability of the system.
### 2.4 High - Voltage Tolerance
- The I/O pins of the PCF8574T/3 can tolerate a relatively high voltage. This allows it to interface with external devices that operate at different voltage levels, providing better compatibility with a wide range of sensors and actuators.
## 3. Functional Description
### 3.1 Input Operation
- When an I/O pin is configured as an input, the PCF8574T/3 samples the voltage level on that pin. The sampled data is then made available on the I2C bus. The host device can read this data by sending a read command over the I2C bus.
- For example, if a sensor is connected to an input pin, the PCF8574T/3 can read the sensor's output and transmit the data to the microcontroller for further processing.
### 3.2 Output Operation
- When an I/O pin is configured as an output, the host device can send data over the I2C bus to set the logic level (high or low) of the output pin. The PCF8574T/3 then drives the corresponding output pin to the specified voltage level.
- This can be used to control external devices such as LEDs, relays, or motors. For instance, if an LED is connected to an output pin, the microcontroller can turn the LED on or off by sending appropriate commands to the PCF8574T/3.
## 4.
Images for reference
16-SOIC_SOT162-1
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