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Low power I2C isolation

Darren DeBattista1
Intellectual 445 points
Other Parts Discussed in Thread: ISO1541, ISO7041

Hi,

I am searching for a low power I2C isolation. By low power, I mean that in idle state, the isolation IC should have quiescent current in the uA range. I did some search and found the ISO7041. This is a 3/1 isolator IC mostly suitable for SPI. Is there something similar for I2C (like the ISO1541 but with very low quiescent current)?

Thanks

  • 0
    TI__Genius 17100 points

    Hi Darren,

    Although we do not have a version of the ISO1541 with very low Iq, an option you may consider is to use the ISO7041 to create an isolated I2C interface as described in this design and shown below.



    Does the MCU have separate SDAI and SDAO pins? If that's the case, there might be another option as well. Please let me know if you have additional questions! I will await your response.


    Thank you for your time,
    Manuel Chavez

  • 0 in reply to Manuel Chavez
    Intellectual 445 points

    Hi Manuel,

    Thanks for your reply. I'll go through the design. As for separate IOs, the MCU also has an SPI peripheral but the I2C peripheral only has a single data line SDA .I actually never saw an I2C bus with separate SDAI and SDAO lines.  Is the SPI peripheral used in such a case?

    Thanks

  • 0 in reply to Darren DeBattista1
    TI__Genius 17100 points

    Hi Darren,

    You're welcome! It is common for MCUs to have a single data line for SDA, but some MCUs and data converters may have separate pins for SDAI and SDAO although I can't say whether they involve an SPI peripheral or not. Separate SDAI and SDAO lines would allow for a different method to create an isolated I2C interface, but it is not necessary in this case since the design above will work.

    Please feel free to reply here or create a new thread if you have more questions with this design or any others!


    Thank you for posting to E2E,
    Manuel Chavez