PCF8574ADWRG4

I/o Expanders Overview

The PCF8574ADWRG4 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 standard-mode clock frequencies up to 100 kHz. The device features an open-drain interrupt output (INT) and quasi-bidirectional I/O ports (P0–P7). It is housed in a 16-pin SOIC package with an operating temperature range from -40°C to +85°C.

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: filter units
• Servers
• Routers (telecom switching equipment)
• Personal computers
• Products with GPIO-limited processors

I/o Expanders Procurement Notes

Verify the specific ordering suffix 'DWRG4' against the manufacturer's current orderable addendum to confirm the exact package type and tape-and-reel specifications. Ensure the component meets RoHS compliance requirements as indicated by the 'G4' designation. Cross-reference the datasheet revision date to confirm the accuracy of electrical characteristics before finalizing procurement.

I/o Expanders Selection Notes

Select this component when expanding microcontroller I/O capabilities using the I2C protocol. It is suitable for applications requiring low standby current consumption and direct LED driving without external drivers. Verify that the system voltage falls within the 2.5 V to 6 V range and that the I2C bus capacitance does not exceed 400 pF for reliable operation at standard mode speeds.

I/o Expanders Part Context

This part belongs to the PCF8574A family of remote 8-bit I/O expanders. The 'DW' suffix indicates the 16-pin SOIC package, while 'RG4' typically denotes lead-free packaging and environmental compliance. Other variants in the series include different packages such as TSSOP, VQFN, and PDIP, offering flexibility for various PCB layout constraints.

I/o Expanders Replacement Considerations

PCF8574APWRE4

I/o Expanders FAQ

How is the interrupt signal reset?

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

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

At power-on, all I/Os are high. In this mode, only a current source to VCC is active, allowing them to be used as inputs after being pulled high.

Can the I/Os be used as inputs without a direction control signal?

Yes, each quasi-bidirectional I/O can function as an input or output without requiring a separate data-direction control signal.