ISO1540 Compatible STEMMA QT / Qwiic Bidirectional I2C Isolator Module

Protect your microcontroller and sensitive components with the ISO1540 Compatible Bidirectional I2C Isolator Module. Designed for makers, engineers, and electronics enthusiasts, this compact board provides robust galvanic isolation on your I2C bus — keeping high-voltage or noisy circuits safely separated from your main logic board without interrupting communication.

Whether you're building an industrial sensor array, a home automation project, or a complex robotics system, this isolator module ensures clean, reliable data transfer across isolated power domains. The plug-and-play STEMMA QT and Qwiic connectors make wiring effortless — no soldering required for most setups.

Key Features

ISO1540 Chip: Industry-standard bidirectional I2C digital isolator supporting both SDA and SCL lines
STEMMA QT & Qwiic Compatible: Standard 4-pin JST SH connectors for rapid, tool-free integration with popular dev boards
Bidirectional Communication: Full I2C pass-through in both directions — works seamlessly as a controller or peripheral side
Galvanic Isolation: Electrically isolates I2C bus to protect sensitive microcontrollers from voltage spikes and ground loops
Low Power Consumption: Efficient design ideal for battery-powered and embedded applications
Breadboard & PCB Friendly: Standard 0.1" (2.54mm) pitch header pins for versatile prototyping
Wide Voltage Support: Compatible with 3.3V and 5V logic levels
Compact Form Factor: Small footprint fits easily into tight enclosures and project builds

What's in the Box

1× ISO1540 Bidirectional I2C Isolator Module
STEMMA QT / Qwiic JST SH connectors pre-installed

Ideal For

Arduino, Raspberry Pi, and CircuitPython / MicroPython projects
Industrial sensor and actuator interfacing
Motor driver and high-voltage circuit isolation
Medical, robotics, and IoT prototyping
Any application requiring safe electrical separation of I2C buses

Compatible With

Works with any STEMMA QT or Qwiic ecosystem board — including Adafruit, SparkFun, and compatible development boards running 3.3V or 5V I2C. Also compatible with standard I2C breakout modules via header pins.

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Frequently Asked Questions

Q: What does the ISO1540 Bidirectional I2C Isolator Module do?

A: The ISO1540 Bidirectional I2C Isolator Module electrically isolates your I2C bus using galvanic isolation technology. It allows bidirectional communication on both SDA and SCL lines while preventing voltage spikes, ground loops, and electrical noise from passing between your controller and peripheral circuits — keeping your microcontroller and sensors safe in demanding or high-voltage environments.

Q: Is the ISO1540 module compatible with Arduino and Raspberry Pi?

A: Yes! The module supports 3.3V and 5V I2C logic levels, making it compatible with Arduino, Raspberry Pi, Adafruit CircuitPython boards, SparkFun Qwiic ecosystem boards, and any other platform with a standard I2C interface. The STEMMA QT and Qwiic JST SH connectors allow for quick, solder-free connections on most development boards.

Q: Do I need to solder to use this I2C isolator module?

A: Not necessarily. If your development board features STEMMA QT or Qwiic ports, you can connect this module with a compatible JST SH cable — no soldering required. For custom PCB or breadboard setups, standard 0.1" pitch header pins are also available for easy integration.

Q: What is the difference between STEMMA QT and Qwiic connectors?

A: STEMMA QT (by Adafruit) and Qwiic (by SparkFun) use the same JST SH 4-pin connector standard and are electrically identical — both carry VCC, GND, SDA, and SCL on the same pinout. This means STEMMA QT and Qwiic cables and boards are fully interchangeable, and this isolator module works with both ecosystems right out of the box.

Production & Packaging Notice

To maintain high stock availability and fast shipping times, our items are sourced from multiple verified manufacturing facilities. While the core quality, materials, and product specifications remain identical, you may notice slight variations in the packaging design, manufacturing origin, or the wording of the printed instructions.