Overview
The PCF8574PWR, manufactured 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 via the I2C interface, which includes serial clock (SCL) and serial data (SDA) pins. It operates within a voltage range of 2.5V to 6V, making it versatile for various applications. The PCF8574PWR features an 8-bit quasi-bidirectional I/O port (P0–P7) that can be used as inputs or outputs without the need for a data-direction control signal. At power-on, the I/Os are initialized as inputs with a weak internal pull-up current source.
Key Specifications
| Parameter | Value |
|---|---|
| Operating Voltage (VCC) | 2.5V to 6V |
| Operating Temperature Range | -40°C to 85°C |
| I2C Bus Frequency | Up to 100 kHz |
| Number of I/O Ports | 8 (P0–P7) |
| I/O Port Type | Quasi-bidirectional |
| Interrupt Output | Open-drain, active LOW |
| Low Standby-Current Consumption | 10 µA max |
| Package Types | TSSOP (20 pins), SOIC (16 pins), PDIP (16 pins), TSSOP (20 pins), QFN (16 pins), VQFN (20 pins) |
| Latch-Up Performance | Exceeds 100 mA per JESD 78, Class II |
Key Features
- I2C to parallel-port expander
- Open-drain interrupt output for indicating input state changes
- Compatible with most microcontrollers
- Latched outputs with high-current drive capability for directly driving LEDs
- Low standby-current consumption of 10 µA max
- Three hardware address inputs allowing up to 16 devices on the same I2C bus
- Internal Power-On Reset (POR) initializes I/Os as inputs with a weak internal pull-up current source
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 PCF8574PWR?
The PCF8574PWR operates within a voltage range of 2.5V to 6V. - What is the maximum I2C bus frequency supported by the PCF8574PWR?
The PCF8574PWR supports up to 100 kHz I2C bus frequency. - How many I/O ports does the PCF8574PWR have?
The PCF8574PWR has 8 quasi-bidirectional I/O ports (P0–P7). - What type of interrupt output does the PCF8574PWR feature?
The PCF8574PWR features an open-drain interrupt output that is active LOW. - What is the low standby-current consumption of the PCF8574PWR?
The low standby-current consumption of the PCF8574PWR is 10 µA max. - Can multiple PCF8574PWR devices be connected on the same I2C bus?
Yes, up to 16 devices can be connected on the same I2C bus due to the three hardware address inputs. - What is the latch-up performance of the PCF8574PWR?
The latch-up performance exceeds 100 mA per JESD 78, Class II. - How are the I/O ports initialized at power-on?
The I/O ports are initialized as inputs with a weak internal pull-up current source at power-on. - Can the PCF8574PWR directly drive LEDs?
Yes, the PCF8574PWR has latched outputs with high-current drive capability for directly driving LEDs. - What are some common applications of the PCF8574PWR?
Common applications include telecom shelters, servers, routers, personal computers, personal electronics, industrial automation, and products with GPIO-limited processors.
