Have you tried a series resistor

"Rs may be required in HS mode as

well as XT mode to avoid overdriving crystals with low drive

level specification."

Regards

Francois



> I'm experiencing about a 3% failure rate on my PIC-based product.  Except
> for one time that a wire was cut, the rest of the time it's been the 20MHz
> crystal that's died.  I'm using a 16C58B chip and the crystal is an
Abracon
> ABL-20.000MHZ-B2.  Is this a normal failure rate for this type of crystal?
> Also, I'm not sure what the two capacitors should be.  Right now, I'm
using
> 33pF capacitors with the crystal, but from what I read in the PIC manual
> that may not be right.  The PIC manual recommends 15pF, but there's a note
> that it should be 30pF if VDD > 4.5 (I'm using a 78L05 so VDD is 5 volts),
> and Abracon lists "Shunt capacitance" for this crystal at 7pF & "Load
> Capacitance" at 18pF.  Being almost totally ignorant of circuit design,
I'm
> not sure what the right capacitors are, so I'm blindly using what someone
> else told me to use, but could using a capacitor that's too big cause
these
> failures?
>
> Thanks
> -Mark

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