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Original question:

ISO1410: Communication error when noise testing

ISO1410: Will a switching inductor used on the back of a board using this device be too noisy for this chip?

Lauren Mayfield
Expert 7985 points
Part Number: ISO1410


Do you forsee any issues with noise for this device if I put a switching inductor on the backside of the board that this chip is mounted on?

  • 0
    TI__Genius 17100 points

    Hi Lauren,

    Thank you for posting to E2E! Please share the following additional information to help us understand this application of ISO1410:

    1. Which signal, power, or GND lines is the switching inductor on the backside of the board connected to?
    2. How much power is this inductor storing / dissipating?
    3. Where exactly is this inductor placed, and on which side of the isolation barrier?
    4. Are you specifically concerned with radiated noise or conducted noise from the switching inductor coupling into the ISO1410 subsystem?

    A schematic of the system and PDF of the PCB layout may be most insightful to share for us to confirm, and if you would like to share those privately, please feel free to send me a Request to Connect and PM.


    Thank you,
    Manuel Chavez

  • 0 in reply to Manuel Chavez
    TI__Expert 7985 points

    Hey Manuel,

    Thanks for your response!

    They are really concerned with the inductive voltage ringing on the pads of a push pull transformer mounted under the ISO1410. Without any guidance, they moved it away some. The transformer is a toroid, so there should be minimal inductive effects from the transformer. It would be good to get some guidance on how close they can mount something like this to the ISO1410.

  • 0 in reply to Lauren Mayfield
    TI__Genius 17100 points

    Hi Lauren,

    You're welcome!

    Explicit guidance is not necessary since our isolators are usually not sensitive to conducted emissions on the supply or on I/O lines due to to good CMTI and I/O logic structure.

    The internal communication frequency in ISO14xx devices is also much higher (100s of MHz) than push-pull power supply switching frequencies (100s of kHz). Due to this difference, we don't expect these switching nodes to affect the isolator's performance, and mounting the transformer on either side of the PCB should not be an issue.

    We do recommend that our customer perform all needed EMC tests on their end product to confirm desired operation.


    Thank you!
    Manuel Chavez