Overview
The PCF8574DWR, 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 for most microcontroller families. It operates within a voltage range of 2.5V to 6V and provides an efficient way to expand the I/O capabilities of a microcontroller via the I2C interface.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Operating Voltage (VCC) | 2.5 to 6 | V |
| Operating Temperature | -40 to 85 | °C |
| Standby Current | 10 | μA |
| I/O Port Type | Quasi-bidirectional | |
| I2C Clock Frequency | Up to 400 kHz | |
| Interrupt Output Type | Open-drain | |
| Output Drive Capability | Up to 25 mA | |
| Package Types | SOIC (16), TSSOP (20), PDIP (16), QFN (16), VQFN (20) |
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
- Latch-up performance exceeds 100 mA per JESD 78, Class II
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 PCF8574DWR?
The operating voltage range is 2.5V to 6V. - What is the maximum I2C clock frequency supported by the PCF8574DWR?
The maximum I2C clock frequency is up to 400 kHz. - What type of interrupt output does the PCF8574DWR have?
The PCF8574DWR has an open-drain interrupt output. - What is the standby current consumption of the PCF8574DWR?
The standby current consumption is 10 μA max. - Can the PCF8574DWR directly drive LEDs?
Yes, the device has latched outputs with high-current drive capability for directly driving LEDs. - What are the package types available for the PCF8574DWR?
The available package types include SOIC (16), TSSOP (20), PDIP (16), QFN (16), and VQFN (20). - How does the interrupt function work on the PCF8574DWR?
The interrupt is generated by any rising or falling edge of the port inputs in the input mode. It can be reset by changing the data on the port or by reading from or writing to the port that generated the interrupt. - What is the maximum bus capacitance for the I2C bus when using the PCF8574DWR?
The maximum bus capacitance must not exceed 400 pF for standard-mode or fast-mode operation. - How does the power-on reset feature work on the PCF8574DWR?
The power-on reset feature resets the I2C-bus logic and sets all I/Os to logic high when VCC is below the power-on reset threshold. It requires a power cycle to reset the device completely. - What are some common applications of the PCF8574DWR?
Common applications include telecom shelters, servers, routers, personal computers, personal electronics, industrial automation, and products with GPIO-limited processors.
