Overview
The PCF8574ANG4, 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 to provide general-purpose remote I/O expansion for most microcontroller families via the I2C interface, which includes serial clock (SCL) and serial data (SDA) lines. It operates within a voltage range of 2.5V to 6V, making it versatile for various applications. The PCF8574ANG4 features an 8-bit quasi-bidirectional I/O port (P0–P7), allowing each port to be used as either an input or output without the need for a data-direction control signal. At power-on, the I/Os are set high, with only a current source to VCC active.
Key Specifications
| Specification | Value | Unit |
|---|---|---|
| VCC Operating Voltage | 2.5 to 6 | V |
| Number of I/O Ports | 8 | - |
| I/O Port Type | Quasi-bidirectional | - |
| I2C Clock Frequency | 100 kHz | Hz |
| Interrupt Output | Open-drain | - |
| Standby Current Consumption | 10 μA (max) | A |
| Package Types | PDIP (16), SOIC (16), TSSOP (20), TVSOP (20), VQFN (20) | - |
| Body Size (Nominal) | Varies by package (e.g., PDIP: 19.30mm × 6.35mm, SOIC: 10.30mm × 7.50mm) | mm |
Key Features
- Low standby-current consumption of 10 μA max
- I2C to parallel-port expander
- Open-drain interrupt output
- Compatible with most microcontrollers
- Latched outputs with high-current drive capability for directly driving LEDs
- Quasi-bidirectional I/O ports (P0–P7) that can be used as inputs or outputs without data-direction control signals
- Strong pull-up and pull-down capabilities for fast rising and falling edges
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 operating voltage range of the PCF8574ANG4?
The PCF8574ANG4 operates within a voltage range of 2.5V to 6V.
- How many I/O ports does the PCF8574ANG4 have?
The device features 8 quasi-bidirectional I/O ports (P0–P7).
- What type of interrupt output does the PCF8574ANG4 provide?
The device provides an open-drain interrupt output.
- What is the maximum standby current consumption of the PCF8574ANG4?
The maximum standby current consumption is 10 μA.
- Can the I/O ports be used as both inputs and outputs?
Yes, each quasi-bidirectional I/O port can be used as either an input or output without the need for a data-direction control signal.
- What is the I2C clock frequency supported by the PCF8574ANG4?
The device supports an I2C clock frequency of up to 100 kHz.
- What types of packages are available for the PCF8574ANG4?
The device is available in PDIP (16), SOIC (16), TSSOP (20), TVSOP (20), and VQFN (20) packages.
- Can the PCF8574ANG4 directly drive LEDs?
Yes, the latched outputs have high-current drive capability for directly driving LEDs.
- What are some common applications of the PCF8574ANG4?
Common applications include telecom shelters, servers, routers, personal computers, personal electronics, industrial automation, and products with GPIO-limited processors.
- How does the interrupt output work on the PCF8574ANG4?
The interrupt output is generated by any rising or falling edge of the port inputs in the input mode and can be connected to the interrupt input of a microcontroller.
