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Texas Instruments PCF8574RGYR — Interface & Transceivers

TI PCF8574RGYR I²C 8-bit GPIO Expander, 100 kHz, 20-VQFN

MPNPCF8574RGYR
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Texas Instruments PCF8574RGYR, I²C 8-bit GPIO expander, 100 kHz clock, 2.5V–6V supply, 25 mA sink / 1 mA source per I/O, 20-VQFN (3.5x4.5) package, -40°C to 85°C.

$0.9360Ref. price · indicative, final on quote
Texas Instruments PCF8574RGYR datasheet (PDF)
Independent supplier — new & surplus stockAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

PCF8574RGYR 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
Case20-VFQFN Exposed Pad
Interrupt outputYes

Product details

I²C GPIO expander in a 20-VQFN package

The part features a power-on reset (POR) circuit that initializes the I/O ports to a known state, an interrupt output that signals the host on input changes, and push-pull output drivers. The 100 kHz I²C clock frequency is suitable for polling GPIOs at moderate rates — think reading panel buttons, driving indicator LEDs, or latching relay states in industrial control panels and building automation terminals.

Output drive — sink vs source asymmetry

The rated output current is 25 mA sink and 1 mA source per I/O. This asymmetry is the main design constraint: the 25 mA sink can directly drive an LED with a series resistor or a small relay coil, but the 1 mA source limit means you cannot source enough current to bias a typical LED — use a pull-up to the supply or drive the load low-side. If your application needs to source more than 1 mA per pin, consider adding external transistors or selecting a different expander variant.

Frequently asked questions

What is the I2C address of PCF8574RGYR?

The I²C address is determined by the A0, A1, and A2 address pins. The base address for the PCF8574 is 0x20 (0100000), and each address pin adds a binary weight. With all three pins tied low, the address is 0x20. The PCF8574A variant uses a different base address (0x38) to allow up to 16 devices on the same bus.

What is the difference between PCF8574RGYR and PCF8574PWR?

The two parts share the same I²C GPIO expander core with identical electrical specifications — 100 kHz clock, 2.5 V to 6 V supply, 25 mA sink per I/O. The difference is the package: PCF8574RGYR comes in a 20-VQFN (3.5x4.5 mm) with an exposed thermal pad, while PCF8574PWR uses a 20-TSSOP. The VQFN package saves board area and offers better thermal performance through the pad; the TSSOP is easier to hand-solder and inspect.