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ISO7742: Could you tell me about the communication noise immunity of ISO7242 V.S. ISO7742 ?

Part Number: ISO7742

Hi, team.

My customers are considering ISO7242 as an alternative to ISO7742.

When customers tested the communication noise immunity of these two devices, it says that ISO 7742 is better.

So question.

① Do you think the result is correct?

② If the answer to "①" is "YES", what is the cause of this difference?

Best regards,

Masumi Sekiguchi

  • Hi Masumi,

    ISO7742 belongs to our latest family of digital isolators. We have implemented various circuit improvements within the device.
    Because of these improvements ISO7742 is expected to be better in performance and EMC/EMI/Immunity than the older family of ISO7242 devices.

    Regards,
    Anand Reghunathan

  • In reply to Anand Reghunathan:

    HI, Reghunathan-san.


    For example, what kind of points did you improve?

    ※Please tell me in a range that does not cause any problems.

    Best regards,

    Masumi Sekiguchi

  • In reply to Pokkun:

    Hi Masumi-san,

    ISO7742 is based on a different architecture (On-Off Keying) than ISO7242 architecture (Edge Based). Please refer to link below to see differences in the architecture.

    Digital Isolator Design Guide

    Let me know if any additional details are required.

    Regards,

    Anand Reghunathan

  • In reply to Anand Reghunathan:

    Thank you for contacting me.

    I have seen the document.
    Please tell me about additional questions from the customer.

    Have you changes in materials (pre-process etc) in the process of architecture change?
    ※Or, are the circuit configuration only changed?

    Best regards,

    Masumi Sekiguchi
  • In reply to Pokkun:

    Hi Masumi-San,

    The major reason for improvement in noise immunity is because of change in the architecture from edge based keying to On-Off Keying. This is mostly done through circuit configuration change.
    In On-Off Keying architecture the presence of carrier would mean one state and its absence means the other state hence the information in carrier is always conveyed to output unlike Edge-based architecture where information is conveyed only when there is a transition at input signal.
    Apart from this there are many enhancements in device to improve ESD, EFT and other EMI performance.

    Regards,
    Anand Reghunathan