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ISO7842: vs ISO7742 + SN6501 for EMI

Guru 12940 points

Part Number: ISOW7842


My customer is selecting ISO device and worried about  "ISOW7842" or "ISO7742+SN6501".

They mind not size but efficiency and EMI(and cost).

I'm understanding that efficiency of ISO7742+SN6501 is greater than ISOW7842.

How about is EMI? Which one is better? 

Please let me know if you have any question.

Best Regards,


  • Hi Kuramochi-san,

    ISO7742+SN6501 will have higher efficiency (~90%) as compared to ISOW7842 (~50%).
    In terms of emissions, ISO7742+SN6501 solution will have better emissions.

    To help you further with your query, could you please clarify what emissions testing/certification is being done on the system? Which emissions standard is being targeted?

    Anand Reghunathan
  • Guru 12940 points

    In reply to Anand Reghunathan:


    Unfortunately, my customer can't open the target EMI Level.
    They consider that the lower EMI is better.

    Could you explain why ISOW7842 is better for EMI than ISO7742 + SN6501?

    Best Regars,
  • In reply to TQ:

    Hi Kuramochi-san,

    One clarification: ISO7742+SN6501 will have better emissions performance than ISOW7842.

    ISO7742 + SN6501 is better because it is a discrete solution operating at lower frequency. This low frequency will not show up in emissions measurements.

    On the other hand, there are a few disadvantages with this discrete solution.

    1. ISO7742 + SN6501 will require a bulky transformer for transferring the power. This will take up a lot more board area as compared to the integrated solution (ISOW7842).
    2. In case of discrete solution, the bulky transformer will need to be separately certified in case of any high voltage isolation certification.If you go with ISOW7842 solution the certification process for the end equipment will be simpler

    I would recommend trying to figure out the target EMI level and if ISOW7842 can meet the specifications, it will definitely be a better solution for customer.
    Let me know. Thanks.

    Anand Reghunathan