Overview
The PCF8574PWG4 is an 8-bit input/output (I/O) expander designed for use with the two-line bidirectional I2C bus. Produced by Texas Instruments, this device is intended for general-purpose remote I/O expansion for most microcontroller families. It operates within a voltage range of 2.5V to 6V VCC and features an 8-bit quasi-bidirectional I/O port (P0–P7) with latched outputs capable of driving LEDs directly. The device 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 in input mode.
Key Specifications
| Parameter | Value |
|---|---|
| VCC Operation Range | 2.5V to 6V |
| I/O Port | 8-bit quasi-bidirectional (P0–P7) |
| Interrupt Output | Open-drain (INT) |
| I2C Interface | Serial clock (SCL), serial data (SDA) |
| Address Inputs | Three hardware address inputs (A0, A1, A2) |
| Package Options | TSSOP (20 pins), SOIC (16 pins), PDIP (16 pins), QFN (16 pins), VQFN (20 pins) |
| Standby Current | 10 μA max |
| Latch-Up Performance | Exceeds 100 mA per JESD 78, Class II |
Key Features
- Latched outputs with high-current drive capability for directly driving LEDs
- Quasi-bidirectional I/O ports that can be used as inputs or outputs without a data-direction control signal
- Open-drain interrupt output (INT) for connection to microcontroller interrupt inputs
- Compatible with most microcontrollers via the I2C interface
- Low standby-current consumption of 10 μA max
- Three hardware address inputs for device addressing
Applications
- Telecom shelters: filter units
- Servers and routers (telecom switching equipment)
- Personal computers and personal electronics
- Industrial automation
- Products with GPIO-limited processors
Q & A
- What is the voltage operation range of the PCF8574PWG4?
The PCF8574PWG4 operates within a voltage range of 2.5V to 6V VCC.
- What type of I/O port does the PCF8574PWG4 feature?
The device features an 8-bit quasi-bidirectional I/O port (P0–P7).
- How does the interrupt output work on the PCF8574PWG4?
The open-drain interrupt output (INT) generates interrupts on rising or falling edges of the port inputs in input mode.
- What is the purpose of the three hardware address inputs on the PCF8574PWG4?
The three hardware address inputs (A0, A1, A2) are used for device addressing.
- Can the PCF8574PWG4 drive LEDs directly?
Yes, the latched outputs have high-current drive capability for directly driving LEDs.
- What is the standby current consumption of the PCF8574PWG4?
The standby current consumption is 10 μA max.
- What are some common applications of the PCF8574PWG4?
Common applications include telecom shelters, servers, routers, personal computers, personal electronics, industrial automation, and products with GPIO-limited processors.
- How many package options are available for the PCF8574PWG4?
The device is available in several package options including TSSOP, SOIC, PDIP, QFN, and VQFN.
- Is the PCF8574PWG4 compatible with most microcontrollers?
Yes, it is compatible with most microcontrollers via the I2C interface.
- What is the latch-up performance of the PCF8574PWG4?
The latch-up performance exceeds 100 mA per JESD 78, Class II.
