I have seen crystals damaged by overdriving during in-circuit test (bad
programing).

> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]]On Behalf Of Jason
> Sent: Monday, April 22, 2002 12:24 PM
> To: [log in to unmask]
> Subject: [TN] 20 Mhz crystal start-up woes
>
>
> Has anyone had difficulty with crystal start-up.
> Currently we are having problems with a circuit that uses a PIC16C711-
> 201/P, 2 @ 22pF load caps and a 20 Mhz AT crystal. The
> configuration is for
> fundamental operation.
>
> We are using a high temp screen (85 deg C storage before functional check)
> to try and weed out problems but have still found modules not
> functional at
> the production plant.
> Sleepy crystals have been discussed but we have experimented with three
> different manufactures of crystals we have ruled this out.
> One of our action items is to redesign and use 10 Mhz, but right now we
> aren't sure of the root cause of failure so there really isn't a guarantee
> that this plan will work.
>
> What are some specific design parameters that could be measured to arrive
> at the root cause?
>
> Thanks,
> Jason
>
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