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Texas Instruments PCF8574ADWR — Interface & Transceivers

PCF8574ADWR I2C I/O Expander, 8-Bit, 2.5V–6V, 16-SOIC

MPNPCF8574ADWR
Active

Texas Instruments PCF8574ADWR, 8-bit I2C I/O expander, 2.5V–6V supply, 100 kHz clock, push-pull outputs, POR, interrupt output, -40°C–85°C, 16-SOIC.

$1.9500Ref. price · indicative, final on quote
Texas Instruments PCF8574ADWR datasheet (PDF)
Independent supplier — new & surplus stockAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

PCF8574ADWR 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
PackageTape & Reel (TR); Cut Tape (CT)
FeaturesPOR
Number of i (O)8
Case16-SOIC (0.295\", 7.50mm Width)
Interrupt outputYes

Product details

Active production, wide supply — a clean I/O expander for mixed-voltage boards

It operates from 2.5V to 6V, so it bridges 3.3V and 5V logic domains without a level shifter on the I2C lines. The 100 kHz clock rate matches standard-mode I2C, and the push-pull outputs sink 25 mA per pin — enough to drive an LED directly or switch a small relay through a transistor. An open-drain interrupt output (INT) signals the host when an input state changes, letting the MCU sleep until activity occurs rather than polling the bus.

Pin-compatible alternative — PCF8574 vs PCF8574A

The PCF8574ADWR is a direct functional replacement for the base PCF8574 (same 8-bit I2C I/O expander, same 16-SOIC footprint, same 2.5V–6V supply range). The difference is the I2C address: the PCF8574A uses a different fixed address block (0x38–0x3F) versus the PCF8574 (0x20–0x27), allowing up to 16 expanders on the same bus when both variants are used. If your BOM already specifies the PCF8574, the PCF8574ADWR swaps in with a firmware address change only.

Frequently asked questions

Is PCF8574ADWR a direct replacement for the PCF8574?

Yes, the PCF8574ADWR is a direct functional replacement for the PCF8574. Both are 8-bit I2C I/O expanders in the same 16-SOIC package with the same 2.5V–6V supply range. The only difference is the I2C address block: the PCF8574A variant uses addresses 0x38–0x3F, while the base PCF8574 uses 0x20–0x27. Firmware must be updated to match the new address.

Does PCF8574ADWR have an interrupt output?

Yes, the PCF8574ADWR includes an interrupt output (INT) that asserts low when any input pin changes state, allowing the host MCU to avoid polling the I2C bus.

What is the I2C address of the PCF8574ADWR?

The PCF8574ADWR uses the PCF8574A address block (0x38–0x3F), selectable via the A0, A1, A2 address pins. This differs from the base PCF8574 which uses 0x20–0x27.