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AMC1303M2520: how does Method B1 screens out against contamination inside SiO2 isolation?

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Replies: 3

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Part Number: AMC1303M2520

Hi, Team.

I've been asked by customer how Method B1 test screes "contamination" out by taking place Method B1 Partial discharge test?

I know that Method B1 is composed of 2 different purpose test , 1 is for HV withstand capability test and wipe the contamination out though,

how does "taking place Method B1 partial discharge test" screen out for contamination?

could you tell me?

I've referred below our document.

"The second part of Method-B1 is a 1 second partial discharge test at “Vm” which is >/= 1.875x VIORM for reinforced isolation. The partial discharge test screens out units with electrically active voids in the mold compound"

http://www.ti.com/lit/wp/sszy028/sszy028.pdf

Thanks.

Best Regards.,

  • Hi Takahashi-san,

    Partial discharge testing looks for voids or air gaps in the mold compound.  The dielectric coefficient of air is lower than that of the mold compound which causes the electric field strength around the void to be higher than the rest of the insulation material.  Since the dielectric strength of air is lower than that of the mold compound, you can have an electrical discharge in the void.  These discharge events is what the test screens for.

     

    Regards,

    Tom

  • In reply to Tom Hendrick:

    Hi, Tom-san

    thanks your reply.

    Can we happen to assume that there would have much small void in the mold compound what partial discharge can't screen out?

    sorry but I don't know how much coefficient those are different.

    Thanks.

    Best Regards.,

  • In reply to Masaharu Takahashi:

    Hi Takahashi-san,

    The tests described in IEC 60747-5-6 are meant to screen out defects in the isolation capacitors and the mold compound.  If there are small voids in the mold compound that do not cause issues with the PD test, then it should not be a problem.

     

    Regards,

    Tom