Overview
The PCF8574APWRG4, 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 provides general-purpose remote I/O expansion for most microcontroller families, operating within a voltage range of 2.5V to 6V. It features an 8-bit quasi-bidirectional I/O port (P0–P7) with latched outputs, enabling high-current drive capability to directly drive LEDs. Each I/O can function as either an input or output without the need for a data-direction control signal. At power-on, the I/Os are initialized as high, with only a current source to VCC active.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| VCC Supply Voltage Range | 2.5 to 6 | V |
| Input Voltage Range | -0.5 to VCC + 0.5 | V |
| Output Voltage Range | -0.5 to VCC + 0.5 | V |
| Continuous Output Low Current | 50 | mA |
| Continuous Output High Current | -4 | mA |
| Operating Temperature Range | -40 to 85 | °C |
| I2C Bus Frequency | 100 kHz | |
| Package Types | VQFN (20), PDIP (16), SOIC (16), TSSOP (20), TVSOP (20) | |
| Standby Current Consumption | 10 µA (max) |
Key Features
- 8-bit quasi-bidirectional I/O port (P0–P7) with latched outputs and high-current drive capability for directly driving LEDs.
- Compatible with most microcontroller families via the I2C interface (serial clock (SCL), serial data (SDA)).
- Low standby-current consumption of 10 µA (max).
- Open-drain interrupt output (INT) for indicating input state changes.
- Three hardware address inputs allowing up to 16 devices on the same I2C bus, supporting up to 128 I/Os.
- Internal Power-On Reset (POR) initializes I/Os as inputs with a weak internal pull-up current source.
Applications
- Remote I/O expansion for microcontrollers in various applications such as industrial control systems, consumer electronics, and automotive systems.
- Driving LEDs and other indicator devices directly due to high-current drive capability.
- Monitoring interrupt status or keypads in input mode.
- Mobile applications due to low current consumption).
Q & A
- What is the operating voltage range of the PCF8574APWRG4?
The operating voltage range is from 2.5V to 6V).
- What is the maximum continuous output low current of the PCF8574APWRG4?
The maximum continuous output low current is 50 mA).
- How many devices of the PCF8574APWRG4 can be connected on the same I2C bus?
Up to 16 devices can be connected on the same I2C bus, supporting up to 128 I/Os).
- What is the purpose of the interrupt output (INT) in the PCF8574APWRG4?
The interrupt output (INT) is used to indicate to the microcontroller that an input state has changed, eliminating the need for continuous polling).
- What is the standby current consumption of the PCF8574APWRG4?
The standby current consumption is 10 µA (max)).
- Can the PCF8574APWRG4 drive LEDs directly?
- What is the I2C bus frequency supported by the PCF8574APWRG4?
The device supports an I2C bus frequency of up to 100 kHz).
- What are the available package types for the PCF8574APWRG4?
The available package types include VQFN (20), PDIP (16), SOIC (16), TSSOP (20), and TVSOP (20)).
- How are the I/Os initialized at power-on?
The I/Os are initialized as inputs with a weak internal pull-up current source).
- What is the operating temperature range of the PCF8574APWRG4?
The operating temperature range is from -40°C to 85°C).
