Adafruit PCF8575 I2C 16 GPIO Expander Breakout - STEMMA QT / Qwiic

Expand your project possibilities with the Adafruit PCF8575 GPIO Expander Breakout - an affordable and versatile 16-channel I2C expander. Perfect for projects needing additional GPIO pins beyond what your board offers, this breakout provides a simple connection over I2C for controlling and reading up to 16 input/output pins.

The PCF8575 offers three I2C address select jumpers for up to 8 expanders on one bus, allowing 128 total GPIOs to be added. Each pin supports a light pull-up input or a strong low-driving output mode, with an IRQ output to alert on input pin changes. The design uses a unique pin state approach instead of traditional direction registers to reduce complexity.

This breakout features the STEMMA QT form factor with JST-SH connectors compatible with SparkFun Qwiic, enabling solderless connection to your development board or chaining with other STEMMA QT compatible accessories.

• 16 GPIO pins accessible via I2C
• Up to 8 expanders on one bus using address jumpers for 128 GPIOs total
• Light pull-up input or strong ground output pin modes
• IRQ output for input state change alerts
• Compact PCB measuring 40.8mm x 17.7mm x 4.5mm
• Lightweight at 2.6g
• STEMMA QT / Qwiic JST-SH connectors for easy plug-and-play wiring (cables not included)

Ideal for expanding buttons, switches, LEDs, and other GPIO needs in your embedded projects. Compatible with Arduino and CircuitPython libraries that simplify handling the pin modes and states.