Re: [WP34S] Crystal Message #11 Posted by uhmgawa on 27 Oct 2011, 8:50 p.m., in response to message #7 by Kerem Kapkin (Silicon Valley, CA)
Quote:
I noticed one can get several different type capacitors ie ceramic, thin film, etc in 0603 SMD with different tolerances 5%, 3% or 2%. Would anything work, or one better than the other for this application? Any suggestions.
From a temperature/environmental stability perspective: polystyrene dielectric if you can still find them. Outside of military/esoteric
capacitors they were the choice for timing critical applications.
Unfortunately they are only available in leaded packages, though
quite minuscule and inexpensive at the values required here.
Failing that an NPO/COG ceramic.
But yes, this will address drift only and you'll need to compensate
the xtal to the intended frequency if that's needed.
Another thought is to forego absolute accuracy of the xtal oscillator in favor of stability, and compensate for whatever
off-target frequency exists numerically.
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