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ISO7841: ISO7841 output signal becomes high with space electromagnetic interference test

Yang Wu
Expert 3080 points
Part Number: ISO7841
Other Parts Discussed in Thread: ISO7831, ISO7741

Hi Team,

My customer is using ISO7841, when they do space electromagnetic interference test, they found that,

1. The low level output signal becomes high (but still a little lower than the normal high level output signal);

2. IC temperature becomes high (still needs to test the real temperature later).

3. With power cycle, IC can work normally (which means the space electromagnetic interference test seems doesn't damage the IC).

This also happens when using ISO7831.

Have you ever been met this issue? Could you help to explain? thanks a lot.

Abnormal waveforms:

Normal Waveforms:

Space electromagnetic interference test equipment: https://www.langer-emv.de/en/download/13/160/55/sgz-21-burst-generator.pdf 

Best regards,

Yang

  • 0
    TI__Genius 17100 points

    Hi Yang,

    Thank you for posting on E2E! I'm sorry to hear that you are having this issue with ISO7841. Can you please share additional information about the standard requirement and your end application?

    If possible, testing our other digital isolator devices like ISO7741 or ISO7341 may yield different results meanwhile.


    Thank you,
    Manuel Chavez

  • 0 in reply to Manuel Chavez
    TI__Genius 17100 points

    Hi Yang,

    Thank you for following up with additional information over email. 

    It seems that the tester used in this test applies a stress similar to EFT noise, and our ISO77xx devices have an optimized design compared to ISO78xx for this, so we recommend our customer test ISO7741 in their system instead of ISO7841.

     If ISO7841 must be used, please try to use a 100Ω resistor in series with Vcc.


    Thank you,
    Manuel Chavez

  • 0 in reply to Manuel Chavez
    TI__Expert 3080 points

    Hi Manuel,

     

    Let’s try the 100ohm method, if it doesn’t work, we need to find other solutions. However, currently it’s difficult for customer to move to ISO77xx. They can considering it in next gen.

    thanks a lot.

    Best regards,

    Yang