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ISO784X(ISO7841, ISO7840) - some questions

Hi all,

Would you mind if we ask ISO784X(reiforced degital isolator) series?
 
<Question1>
About Reinforced isolation, the minimum creepage distance which based on IEC60950 is 6.4mm.
In case of ISO784X, we think the shortest distance along the surface of the device is under 6.4mm.
So, it is not problem on IEC60950 standard?
We don't have some knowledge about it.

<Question2>
How much is the capacity of the isolation?
Our customer queries whether the logic will reverse without keeping the load or not.
This device is OOK method.That's why, as our recognition, it is not relation to the capacity of the isolation.

<Quesion3>
Surge immunity is 12.8kV.
What kind of surge immunity is it supposed?
On IEC60060 standard,  it is defined the condition 1.2us/50us.
So, is it(12.8kV) possible to correspond IEC60060(1.2us / 50us)?
Our customer supposes impulse withstand voltage 8kV.

Could you let us know these?
We appreciate your help.

Kind regards,

Hirotaka Matsumoto

  • Matsumoto-san,

    Please see my responses below:

    1) ISO784xDW has Creepage and Clearance of >8mm. This distance has been certified by VDE, CSA and CQC. I'm not sure why you think that Creepage is < 6.4mm.

    2) Cio or 'Input to Output Capacitance' of ISO784x is typically ~ 2pF. This capacitance value is symmetrical and it is provided in the data sheet.

    3) Surge testing is done per IEC 60065 by VDE. VDE requires surge to be tested with 60% margin above the surge voltage rating of 8 kVpk. Therefore the actual testing is done at 12.8 kVpk (= 1.6 x 8 kVpk).  

  • Saleen san

    Thank you for your so very kind reply!

    And, we appologize that we have mis-understanding the package of ISO784xDW.
    We mistaked that  ISO784xDW package is SOIC8.
    Actually,  ISO784xDW is SOIC16 or DW  10.30 mm x 7.50 mm.

    Then, we got your saying.

    Kind regards,

    Hirotaka Matsumoto

  • Saleen san

    We would like to ask one point.

    Our customer asked us how to evaluate‎ withstand voltage test.
    We don't have any idea, so If you have some document, could you give us?

    Kind regards,

    Hirotaka Matsumoto

  • Matsumoto-san,

    I'm not sure I fully understand your question. Are you asking for withstand voltage test data? or the customer wants to perform withstand voltage test and wants to figure out how to perform the test?

    ISO78xx has 5.7 kVrms withstand isolation voltage and it has been proven by certification agencies.

    Withstand isolation voltage test is performed as a two-terminal test, meaning all pins on left side are shorted together and all pins on the right side are shorted together and then high voltage is applied between these two terminals with the help of High voltage tester, also referred to as Hi-pot tester.

  • Saleen san,

    Thank you for your so kind reply!

    Yes, our customer wants to perform withstand voltage test and wants to figure out how to perform the test.
    Thanks to your exlanation, we got it!

    Kind regards,

    Hirotaka Matsumoto