Adafruit ISO1540 Bidirectional I2C Isolator - STEMMA QT / Qwiic

The Adafruit ISO1540 Bidirectional I2C Isolator is designed to provide full electrical isolation between two sides of an I2C bus. Perfect for setups where you need to keep an I2C bus controller and an I2C device electrically separated due to grounding differences, noise reduction, or special power monitoring requirements.

This board uses the TI ISO1540 chip, which supports bidirectional I2C communication up to 1 MHz with clock stretching and operates between 3V to 5.5V on either side separately. It provides 2500 V-RMS isolation for safety and robustness.

The breakout features power, ground, clock, and data breakout pads on each side as well as matching STEMMA QT connectors for easy, solderless connections compatible with SparkFun's Qwiic system.

Key Features:

• Isolated bidirectional I2C communication
• Supports up to 1 MHz operation and clock stretching
• Operates at 3V to 5.5V supply range on each side
• 2500-VRMS isolation to prevent ground loops and noise
• Open-drain outputs with varying sink currents on each side
• Operating temperature range from -40°C to +125°C
• Compliance with safety certifications and ESD protections
• STEMMA QT connectors for easy interconnection and solderless use

The board includes onboard 10K pull-up resistors on each side to their respective power supplies and requires power to be supplied separately on both isolated sides. The green LED indicates power status for each side.

Check out the TI ISO1540 product page for full chip specifications and the Adafruit learning guide for detailed usage instructions.