Overview
The PCF8574DW, 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 2.5V to 6V, making it versatile for various applications. The PCF8574DW features an 8-bit quasi-bidirectional I/O port (P0–P7) that can be used as either inputs or outputs without the need for a data-direction control signal. At power-on, the I/Os are set to high, with only a current source to VCC active.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Operating Voltage (VCC) | 2.5 to 6 | V |
| Operating Temperature Range | -40 to 85 | °C |
| Standby Current Consumption | 10 | µA (max) |
| High-Level Output Current (IOH) | -1 | mA |
| Low-Level Output Current (IOL) | 25 | mA |
| I2C Bus Frequency | 100 | kHz |
| Package Types | SOIC (16), TSSOP (20), QFN (16), VQFN (20), etc. | |
| Junction-to-Ambient Thermal Resistance (RθJA) | 48.3 to 112.2 | °C/W |
Key Features
- I2C to parallel-port expander
- Open-drain interrupt output
- Compatible with most microcontrollers
- Latched outputs with high-current drive capability for directly driving LEDs
- Latch-up performance exceeds 100 mA per JESD 78, Class II
- Low standby-current consumption of 10 µA (max)
- Eight quasi-bidirectional I/O ports (P0–P7)
- Three hardware address inputs
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 operating voltage range of the PCF8574DW?
The PCF8574DW operates within a voltage range of 2.5V to 6V.
- What is the maximum standby current consumption of the PCF8574DW?
The maximum standby current consumption is 10 µA.
- What is the I2C bus frequency supported by the PCF8574DW?
The device supports an I2C bus frequency of up to 100 kHz.
- Can the PCF8574DW drive LEDs directly?
- What types of packages are available for the PCF8574DW?
The device is available in various packages including SOIC (16), TSSOP (20), QFN (16), and VQFN (20).
- Is the PCF8574DW compatible with most microcontrollers?
- What is the purpose of the interrupt output on the PCF8574DW?
The interrupt output is used to signal changes in the input status or other significant events.
- How many quasi-bidirectional I/O ports does the PCF8574DW have?
- What is the operating temperature range of the PCF8574DW?
- Can the PCF8574DW be used in industrial automation applications?
