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Texas Instruments PCF8574DWE4 — Interface & Transceivers

PCF8574DWE4 I²C 8-bit GPIO Expander, 2.5V–6V, 16-SOIC

MPNPCF8574DWE4
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Texas Instruments PCF8574DWE4, I²C 8-bit GPIO expander, 2.5V–6V supply, 100 kHz clock, push-pull outputs, interrupt output, 16-SOIC package, -40°C to 85°C.

$0.5850Ref. price · indicative, final on quote
Texas Instruments PCF8574DWE4 datasheet (PDF)
Independent supplier — new & surplus stockAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

PCF8574DWE4 specifications
ParameterValue
Output typePush-Pull
MountingSurface Mount
Supply voltage2.5V ~ 6V
Current - output source (Sink)1mA, 25mA
Clock frequency100 kHz
InterfaceI²C
Operating temperature-40°C~85°C
PackageTube
FeaturesPOR
Number of i (O)8
Case16-SOIC (0.295\", 7.50mm Width)
Interrupt outputYes

Product details

An interrupt output signals the host MCU when an input changes, reducing polling overhead.

The 2.5 V to 6 V supply range lets the PCF8574DWE4 sit on a 3.3 V MCU bus or a 5 V legacy backplane without a level shifter. If your design needs more than 25 mA per pin, you will need an external transistor or a different expander tier.

Interrupt output — when it matters

The interrupt output (INT) asserts low when any input pin changes state, and stays low until the host reads the port via I²C. This is useful in battery-powered or latency-sensitive systems where continuous polling would waste MCU cycles or power. The INT pin is open-drain, so it can be wire-ORed with other interrupt sources on the same line.

For dual-sourcing resilience, the PCF8574 family includes multiple I²C address variants (PCF8574 vs PCF8574A) that are pin-compatible and differ only in the fixed address bits.

Frequently asked questions

Is the PCF8574DWE4 a direct replacement for the standard PCF8574?

Yes, the PCF8574DWE4 is a direct replacement for the standard PCF8574 in the 16-SOIC package. The 'DWE4' suffix indicates the wide-body SOIC-16 package and the lead-free finish. The electrical specifications — 8 I/O, 100 kHz I²C, 2.5 V to 6 V supply, 1 mA source / 25 mA sink, interrupt output — are identical to the base PCF8574. The I²C address is the same (0x20–0x27, depending on the A0–A2 strapping).

What is the difference between PCF8574 and PCF8574A?

The PCF8574 and PCF8574A are functionally identical — same 8-bit I/O, same I²C protocol, same electrical ratings — but they use different fixed I²C address blocks. The PCF8574 occupies addresses 0x20–0x27, while the PCF8574A occupies 0x38–0x3F. This allows up to 16 expanders on the same bus without address conflict. The PCF8574DWE4 is a PCF8574 variant, so its address range is 0x20–0x27.

Does PCF8574DWE4 have an interrupt output and how does it work?

Yes, the PCF8574DWE4 includes an interrupt output (INT). It is an active-low, open-drain output that asserts when any input pin changes state. The host MCU can connect INT to a GPIO interrupt line; reading the port via I²C clears the interrupt. This eliminates the need to poll the expander over I²C, saving bus bandwidth and MCU cycles.

Where can I find the PCF8574DWE4 datasheet?

The datasheet for the PCF8574DWE4 is available from Texas Instruments under the base product number PCF857. It covers the full family including the PCF8574 and PCF8574A variants. The document includes the I²C protocol timing, register map, application circuits, and thermal derating curves.