Overview
The PCF8574APWG4, 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 part of the PCF8574 family and is intended for general-purpose remote I/O expansion in various microcontroller-based systems. It operates within a supply voltage range of 2.5V to 6V, making it versatile for different application environments. The PCF8574APWG4 features an 8-bit quasi-bidirectional I/O port (P0–P7) and includes latched outputs with high-current drive capability, suitable for directly driving LEDs. The device also includes an 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 | Description |
|---|---|
| Supply Voltage (VCC) | 2.5V to 6V |
| I2C Bus Frequency | Up to 100 kHz |
| I/O Port Configuration | 8-bit quasi-bidirectional (P0–P7) |
| Interrupt Output | Active LOW, generated by rising or falling edges of port inputs |
| Address Inputs | Three hardware address inputs (A0, A1, A2) |
| Package Options | TVSOP (20 pins), SOIC (16 pins), PDIP (16 pins), TSSOP (20 pins), QFN (16 pins), VQFN (20 pins) |
| Operating Temperature Range | -40°C to +85°C |
| Static Supply Current | Typically 2.5 µA at 2.5V VCC |
Key Features
- 8-bit quasi-bidirectional I/O port (P0–P7) with latched outputs and high-current drive capability for driving LEDs.
- Interrupt output (INT) that can be connected to the interrupt input of a microcontroller.
- Three hardware address inputs (A0, A1, A2) allowing multiple devices on the same I2C bus.
- Low current consumption, making it suitable for mobile and battery-powered applications.
- No need for a data-direction control signal; each I/O can be used as an input or output independently.
- Power-on reset feature to ensure I/Os are high at power-up.
Applications
- Remote I/O expansion for microcontroller systems.
- Keyboards and keypad interfaces.
- LED drivers and display control.
- Mobile and battery-powered devices due to low current consumption.
- Industrial control systems requiring additional I/O ports.
Q & A
- What is the operating voltage range of the PCF8574APWG4?
The PCF8574APWG4 operates within a supply voltage range of 2.5V to 6V.
- What is the maximum frequency of the I2C bus for this device?
The I2C bus frequency can go up to 100 kHz.
- How many quasi-bidirectional I/O ports does the PCF8574APWG4 have?
The device features an 8-bit quasi-bidirectional I/O port (P0–P7).
- What is the purpose of the interrupt output (INT) on the PCF8574APWG4?
The interrupt output (INT) generates interrupts on rising or falling edges of the port inputs and can be connected to the interrupt input of a microcontroller.
- How many hardware address inputs does the PCF8574APWG4 have?
The device has three hardware address inputs (A0, A1, A2).
- What is the typical static supply current of the PCF8574APWG4 at 2.5V VCC?
The typical static supply current is 2.5 µA at 2.5V VCC.
- Can the I/O ports of the PCF8574APWG4 be used as both inputs and outputs?
Yes, each quasi-bidirectional I/O can be used as an input or output without the need for a data-direction control signal.
- What happens to the I/O ports at power-on?
At power-on, the I/O ports are high.
- What are some common applications of the PCF8574APWG4?
Common applications include remote I/O expansion, keyboards and keypad interfaces, LED drivers, and industrial control systems.
- Is the PCF8574APWG4 suitable for mobile applications?
Yes, due to its low current consumption, it is suitable for mobile and battery-powered applications.
