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Microphone input Capacitor failing frequently

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Mahen K

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I have the below circuit between the microphone and microphone input of the microcontroller. Every thing works great but the capacitor C37 connected between microphone and microphone input is frequently failing (Open). This has already happened in 5 out of 12 boards. What could be the possible reason? Its a 1206 size SMD ceramic cap with adaquate voltage rating.

Thanks in advance

Mahenk
 

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Most likely an assembly or mechanical stress problem. E.g. a capacitor mounted near to a board edge, that breaks when separating the individual parts of a panel. In most cases, the failure cause can be determined when inspecting the board thoroughly.
 

Hai, Mahen

i'm also faced same problem in one of my project. that problem was due SMD capacitors. voltage also i used higher than system voltage. now i removed that smd type cap and changed normal myler capaitor. now my system running perfectly.

this is my experience........you can think...

Thanks,
Dilan
 

Adequate voltage rating, for what? Your battery voltage,
or maybe stray ungrounded mains voltage until you snug
the plug, acting like ESD?

Since you don't say anything about the failure signature,
there is only speculation. But if it fails shorted, bet on a
zap exceeding rated voltage. Not all ESD matches a
"model" either in form or cause.
 

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