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Questions for your i-coupler device

Dear Sir/Madam,

Our customer have some questions for your i-coupler ADuM3400.


If the internal 2 coils short each other in emergency accident, then what is the output logic H or L fixed?


What is the most strong isolator in over 20Mbps high speed model(series)?

I would like to know what is the lowest FIT value model.

What's recommend for good FIT value?

Because our customer is studying to find high safety level product. Your ADuM34XX models were pickuped in this case.

Thanks in advance. Kaos

  • Hi r.daemon,

    Thanks for your comment here.

    I think so but our customer would like to know "IF HE GET SHORT BETWEEN PRIMARY AND SECONDARY".

    He customer seem to study well IF ?? IF ??,,,,,,,this is applied for the product high level security, I think.

    So after short, the communication seem no problem, correct? 
    Otherwise does work the safety system in i-coupler?

    I could not catch this.


  • Hello Kaos,

    a short circuit between the primary and the secondary coil can happen when the voltage exceeds some thousand volts. I do not think that you will get H or L in such case, but excessive voltage on some of the pins.

    Best regards,

  • Reinhard's response is essentially correct. If a high voltage event creates a short across one of the coils then there would be a relatively low impedance (hundreds to thousands of ohms) between the primary and secondary ground domains. In general all insulating materials and isolators will fail in this way (with a relatively low impedance), including optocouplers

    Once this has occurred, the electrical operation of the isolator cannot be guaranteed. This is becuase hte operation of the isolator is dependant on the transformer characteristics. So the output state would be indeterminate.

    Regarding FIT rates, there's not a major difference between different isolator families since they all use relatively mature silicon processes. ADI's FIT rates are published on our web site. Most of the mature isolators use 0.6 uM CMOS which has FIT < 1.


  • Hi DaveC

    Sorry to my late reply.

    I got it.

    I can inform your comment to our customer.

    Thank you again