> A while back (before the N-bomb stuff, but maybe after the cow stuff)
> someone mentioned a problem with BURNING-OUT crystals by using the wrong
> value resistors.  I'm using 3.58Mhz ceramic oscillators with 56pf caps on
> a batch of 16C554's running at 3.3V from Ni-Cd batteries and NO resistors.
> Could this cause premature failures?

Probably not, although you would really need to have the full specs
from the resonator manufacturer to be sure. It would be nice to have
a bit more info from Microchip on what the oscillator mode switches
do. Do they alter just the frequency response of the amp, the gain,
the o/p impedance or a mixture ?

If you were overdriving the device, you would notice erratic
operation long before it "blew up". The usual symptom of an
overdriven crystal is jumping to overtone and spurious modes so it
appears to run fast. This might be a few percent (spurious) or three
times the rated frequency (overtone) although it can go quite high.
You can get a few MHz out of a 32kHz crystal if you hit it hard
enough.

Steve.
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Steve Baldwin                Electronic Product Design
TLA Microsystems Ltd         Microcontroller Specialists
PO Box 15-680, New Lynn      http://www.tla.co.nz
Auckland, New Zealand        ph  +64 9 820-2221
email: steveb@tla.co.nz      fax +64 9 820-1929
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