Fail shunt regulator, 431, in ESD test?

Question

Hi, all,Shunt regultor, 431, is failure during testing Electrostaticdischarge(ESD). The testing conditon is 10 times 8KV in contact and 10times 15KV in air.I think clearance is short between Vout and 431 on PCB. However, it isnot enough to explain and report.So, let me know why it is happen and what I should do not for happeningagain in the future.You can see the part of circuit and PCB below.Thanks.Bob,

John Fields · Accepted Answer

---Put a TVS across the output and/or across the 431, as required. -- John FieldsProfessional Circuit Designer

Ban · Answer

Look at the datasheet Absolute Maximum Ratings: Reference Input Current Range IREF -0.05 ~ +10 mA

this means you have to avoid *any* negative voltage there above a diode drop. You should clamp that with a Schottky diode on this point or else a

7V5 zener , which would also help with the positive part of the puls.

Pooh Bear · Answer

Is someone actually applying the ESD test directly to a connector pin ? I'mnot surprised it's failing.Graham

Bob J. · Answer

Hi, John Fields,Let me know the TVS, please.Bob.

Pooh Bear · Answer

I see you're looking for a 'band aid' fix rather than finding out whyyour pcb failed a test on its *enclosure* !Graham

Bob J. · Answer

Thank your for your answer friendly, John Fields.Bob.

John Fields · Answer

----- John FieldsProfessional Circuit Designer

Pooh Bear · Answer

I'll venture he can't decrypt the acronym.Graham

John Woodgate · Answer

I read in  that Pooh Bear  wrote (in ) about 'Fail shunt regulator, 431, in ESD test?', on Mon, 29 Aug 2005:Wot's an acronym? I no wot decrypt is; my grandmother's decrypt. She can't walk.-- Regards, John Woodgate, OOO - Own Opinions Only.If everything has been designed, a god designed evolution by natural selection. Also see

Terry Given · Answer

Ye Gods, how much help do you need? RTFPsCheersTerry

Fail shunt regulator, 431, in ESD test?

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