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ISO7731-Q1: ISO7731QDWRQ1 isolation voltage

Hidekazu Someno
Expert 5130 points
Part Number: ISO7731-Q1
Other Parts Discussed in Thread: ISO7731

Hi Team,

My customer was been asking whether ISO7731QDWRQ1 can withstand DC2400V for 60sec from their end customer.

 Q1: This part has the spec of 8000V_pk for 60sec as Viopm.  From this spec., can we estimate that this part can withstand DC2400V for 60sec?

 Q2: The Viopm parameter of the spec of 8000V_pk for 60sec has 100% production test?

 

Regards,

H.Someno

  • 0
    TI__Mastermind 49375 points

    Hi Someno-san,

    Please find below my inputs.

    A1: VIOTM of 8000Vpk is not exactly a DC spec hence, we need not refer to this parameter for finding out device DC performance. Please note that the working voltage of device VIOWM is also quoted in DC as 2121VDC. This is the voltage that ISO7731 in DW package is going to support for >40 years and hence 2400VDC for 60 seconds shouldn't be a problem.

    A2: VIOTM of 8000Vpk is tested for 60 seconds for qualification and for production 100% units are tested for 1.2*VIOTM for 1 second. This means that 100% units are tested for 9600Vpk for 1 second in ATE before they are shipped out of factory to customers. The production test information is also given in datasheet, as shown below.

    Regards,
    Koteshwar Rao

  • 0 in reply to Koteshwar Rao
    TI__Expert 5130 points

    Rao-san,

    Thanks for your reply.

    VIOWM for ISO7731QDWRQ1 on current datasheet(SLLSEU3B)  is 1414V, not 2121V(In non-Q1 datasheet, it is 2121V.).

    Even at  this voltage,  Can you tell that this part withstands 2400VDC for 60 seconds?

    Or, 

    Is 2121V  the correct spec for Q1 part?    If so, is the datasheet spec changed from 1414V to 2121V soon?

    Regards,

    H.Someno

  • 0 in reply to Hidekazu Someno
    TI__Mastermind 49375 points

    Hi Someno-san,

    The device for both industrial and automotive versions are the same, the automotive device goes through additional testing as per automotive requirement (not related to isolation). Hence, 2121VDC of VIOWM will be the working voltage for ISO7731QDWRQ1 as well. The datasheet will be updated during its next major updated to the datasheet.

    To confirm, yes ISO7731QDWRQ1 will also be supporting 2400VDC test for 60 seconds. Thanks.

    Regards,
    Koteshwar Rao

  • 0 in reply to Koteshwar Rao
    TI__Expert 5130 points

    Rao-san,

    There is an additional question related to your answers.

    Customer is requesting a more detailed explanation that we judge that the required 2400V(DC) / 60sec condition is acceptable from the spec. of VIOWM = 2121V(DC) for >40years. (The duration is 60 seconds, but 2400VDC is larger than 2121V).

    Please give more advises to explain it.

    Best regards,

    H.Someno

  • 0 in reply to Hidekazu Someno
    TI__Mastermind 49375 points

    Hi Someno-san,

    Sure. Working voltage of the device is determined by TDDB test, please refer to below TDDB plot of ISO77xx from datasheet (Figure 28). From the plot, you can see that the lifetime of isolation barrier at 2500Vrms is approximately 1E9 seconds which equals to approximately 31.7 years. The lifetime of isolation barrier at 2400VDC is going to be much higher than that of at 2500Vrms and hence, testing device at 2400VDC for 60 seconds not going affect device lifetime much even with sufficient margins.

    Let me know if TDDB data gives confidence to customer on estimating device lifetime, thanks.

    Regards,
    Koteshwar Rao