You can use the Adafruit ISO1540 Bidirectional I2C Isolator to add full electrical isolation between two sides of an I2C bus. The chip we use, the TI ISO1540 is fully bi-directional, supports up to 1 MHz clock rates, supports clock-stretching, works with 3 to 5V DC power or logic (separate on either side of course), with 2500 V-RMS isolation
Usage is easy - you get power/ground/clock/data breakout pads for each side as well as a matching STEMMA QT connector. Unlike our other QT boards, the two sides are obviously electrically isolated, which means each half must be powered! Check that the green LED is lit on both sides. Now send data over I2C and you're good to go. We have 10K pullups on each side, from the I2C pins to the matching VCC for that side.
For more details about chip specifications, check out the TI product page.
To get you going fast, we spun up a custom made PCB in the STEMMA QT form factor, making it easy to interface with. QT Cable is not included.
- Isolated bidirectional, I2C compatible, communication
- Supports up to 1-MHz operation
- 3-V to 5.5-V supply range
- Open-drain outputs With 3.5-mA Side 1 and 35-mA Side 2 sink current capability
- -40°C to +125°C operating temperature
- ±50-kV/μs transient immunity (Typical)
- HBM ESD protection of 4 kV on all pins; 8 kV on bus pins
- Safety-related certifications:
- 4242-VPK isolation per DIN VDE V 0884-11:2017-01
- 2500-VRMS isolation for 1 minute per UL 1577
- CSA approval per IEC 60950-1 and IEC 62368-1 end equipment standards
- CQC basic insulation per GB4943.1-2011