Hi, all,
Shunt regultor, 431, is failure during testing Electrostatic discharge(ESD). The testing conditon is 10 times 8KV in contact and 10 times 15KV in air.
I think clearance is short between Vout and 431 on PCB. However, it is not enough to explain and report.
So, let me know why it is happen and what I should do not for happening again in the future.
You can see the part of circuit and PCB below.
Thanks.
Bob,
-- Put a TVS across the output and/or across the 431, as required.
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.-- ciao Ban Bordighera, Italy
Is someone actually applying the ESD test directly to a connector pin ? I'm not surprised it's failing.
Graham
Hi, John Fields,
Let me know the TVS, please.
Bob.
I see you're looking for a 'band aid' fix rather than finding out why your pcb failed a test on its *enclosure* !
Graham
Thank your for your answer friendly, John Fields.
Bob.
-- http://www.onsemi.com/site/products/parametrics/0,4446,824,00.html
I'll venture he can't decrypt the acronym.
Graham
I read in sci.electronics.design 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. http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
Ye Gods, how much help do you need? RTFPs
Cheers Terry
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