PCF8574PWG4

I/o Expanders Overview

The PCF8574PWG4 is an 8-bit I/O expander for the I2C bus manufactured by Texas Instruments. It operates within a supply voltage range of 2.5 V to 6 V and supports a maximum clock frequency of 100 kHz. The device provides eight quasi-bidirectional I/O pins (P0–P7) and features an open-drain interrupt output (INT). It is housed in a TSSOP-20 package with dimensions of 6.5 mm × 6.4 mm. The component functions across a temperature range from -40°C to +85°C, with a maximum standby current of 10 μA.

I/o Expanders Feature Summary

• Provides remote I/O expansion via the two-line bidirectional I2C interface.
• Features latched outputs with high-current drive capability suitable for directly driving LEDs.
• Includes an open-drain interrupt output that triggers on any rising or falling edge of port inputs.

I/o Expanders Applications

• Telecom shelters including filter units
• Servers and routers for telecom switching equipment
• Personal computers and personal electronics
• Industrial automation systems
• Products with GPIO-limited processors

I/o Expanders Procurement Notes

Verify the specific ordering suffix 'PWG4' against the manufacturer's official documentation to confirm the exact package type and environmental compliance status. Ensure the procurement source provides valid traceability data. Confirm that the component meets all required operating conditions for the intended application environment before finalizing orders.

I/o Expanders Selection Notes

Select this component when expanding microcontroller I/O resources using the I2C protocol. It is suitable for applications requiring operation between 2.5 V and 6 V. Consider the TSSOP-20 package constraints and the need for external pull-up resistors on the SDA and SCL lines. Verify that the system can accommodate the open-drain interrupt logic and the specific address configuration requirements.

I/o Expanders Part Context

The PCF8574 series serves as a general-purpose remote I/O expander designed for most microcontroller families. The PWG4 designation indicates a specific surface-mount variant within the broader PCF8574 family. This component addresses the limitation of available GPIO pins on processors by providing eight additional configurable ports accessible through standard serial communication protocols.

I/o Expanders Replacement Considerations

Consult the manufacturer's official replacement guide for verified substitute part numbers. Ensure any alternative component maintains compatibility with the I2C interface timing requirements and physical package dimensions.

I/o Expanders FAQ

How is the interrupt signal reset?

The interrupt circuit resets when data on the port generating the interrupt is changed to its original setting, or when data is read from or written to that specific port.

What is the behavior of the I/Os at power-on?

At power-on, the I/Os are set to a high state. In this mode, only a current source to VCC is active.

Can the device be used with fast-mode I2C?

The datasheet specifies a maximum clock frequency of 100 kHz for standard-mode operation. Fast-mode operation requires verification against specific electrical characteristics and timing parameters.