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  • TI Thinks Resolved

ISO7721: What is the Maximum transient isolation DC voltage of ISO7721DR

Part Number: ISO7721

Hi Team,

       Customers feedback they used DC 3500V (60 second) to test ISO7721DR's Maximum transient isolation and they found some chip had been broken. (Test 120 chip, 8 chip is broken, broken is  VCC short with GND)

I can't see the Maximum transient isolation DC voltage Vdc in the datasheet. I just saw the Vpk=4242V, which is Maximum transient isolation voltage

Do you have any suggestions for this case? Why have some chips been broken? Can it stand DC 3500V/60 second?

Thanks for your help!

  • Hi,

    ISO7721 should be able to withstand up to 4242 Vdc without any problem. As a matter of fact DC withstand capability of these devices is much stronger than AC withstand capability.  There should be no breakdown of the isolation barrier at 3500Vdc in 60 seconds.

    Saleem Marwat

    Systems Engineer

    Isolation Products, Texas Instruments

  • In reply to Saleem Marwat:

    Hi Saleem,

    Do you have some testing results when device given 4242 Vdc in 60 seconds?
  • In reply to Eggsy Pang:

    Hi Eggsy,

    We've tested this isolation technology with DC voltage that's much higher than 4242 Vdc and we didn't have any failure for several months (not just 60 sec).

    Saleem Marwat

    Systems Engineer

    Isolation Products, Texas Instruments

  • In reply to Saleem Marwat:

    Hi Saleem,
    Well to know it!
    May I know you how to test it? I would like to share the right testing way with my customers!
    Thank you very much!
  • In reply to Eggsy Pang:

    Hi Eggsy,

    High voltage test method is explained in TI Application Report below:
    www.ti.com/.../slla197a.pdf

    Test setup is shown in Figure 2 of this Application Report.

    Saleem Marwat

    Systems Engineer

    Isolation Products, Texas Instruments

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