Overview
The PCF8574DWRE4, produced by Texas Instruments, is an 8-bit input/output (I/O) expander designed for use with the two-line bidirectional I2C bus. This device is intended for general-purpose remote I/O expansion and is compatible with most microcontroller families. It operates within a voltage range of 2.5-V to 6-V VCC, making it versatile for various applications. The PCF8574 features an 8-bit quasi-bidirectional I/O port (P0–P7) with latched outputs, capable of driving LEDs directly due to its high-current drive capability. The device also includes an open-drain interrupt output (INT) that can be connected to the interrupt input of a microcontroller, generating interrupts on rising or falling edges of the port inputs.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| VCC Operating Voltage | 2.5 | - | 6 | V |
| Power-on Reset Voltage (VPOR) | 1.3 | - | 2.4 | V |
| Input Diode Clamp Voltage (VIK) | - | -1.2 | - | V |
| Output High Current (IOH) | - | - | 300 | μA |
| Output Low Voltage (VOL) | - | - | 0.4 | V |
| Package Types | - | - | TVSOP, SOIC, PDIP, TSSOP, QFN, VQFN | - |
| Body Size (Nominal) | - | - | Varies by package (e.g., TVSOP: 5.00 mm × 4.40 mm) | mm |
Key Features
- 8-bit quasi-bidirectional I/O port (P0–P7) with latched outputs
- High-current drive capability for directly driving LEDs
- Open-drain interrupt output (INT) for microcontroller interrupt input
- Compatible with most microcontroller families via I2C interface (SCL, SDA)
- Operates within 2.5-V to 6-V VCC range
- No data-direction control signal required for I/O operation
- Power-on reset circuit sets all I/Os to logic high
Applications
- Telecom Shelters: Filter Units
- Servers
- Routers (Telecom Switching Equipment)
- Personal Computers
- Personal Electronics
- Industrial Automation
- Products with GPIO-Limited Processors
Q & A
- What is the PCF8574DWRE4 used for? The PCF8574DWRE4 is used for general-purpose remote I/O expansion via the I2C interface.
- What is the operating voltage range of the PCF8574DWRE4? The operating voltage range is 2.5-V to 6-V VCC.
- What types of packages are available for the PCF8574DWRE4? The device is available in TVSOP, SOIC, PDIP, TSSOP, QFN, and VQFN packages.
- Does the PCF8574DWRE4 have an interrupt feature? Yes, it features an open-drain interrupt output (INT) that can be connected to the interrupt input of a microcontroller.
- Can the PCF8574DWRE4 drive LEDs directly? Yes, the device has latched outputs with high-current drive capability for directly driving LEDs.
- What is the purpose of the power-on reset circuit in the PCF8574DWRE4? The power-on reset circuit resets the I2C-bus logic and sets all I/Os to logic high.
- Is the PCF8574DWRE4 compatible with most microcontrollers? Yes, it is compatible with most microcontroller families via the I2C interface.
- What are some common applications of the PCF8574DWRE4? Common applications include telecom shelters, servers, routers, personal computers, personal electronics, and industrial automation.
- How does the interrupt circuit work in the PCF8574DWRE4? The interrupt circuit generates interrupts on rising or falling edges of the port inputs and can be reset by changing the data on the port or reading/writing to the port that generated the interrupt.
- Does the PCF8574DWRE4 require a data-direction control signal for I/O operation? No, it does not require a data-direction control signal for I/O operation.
