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Re: [AVR-Chat] What crystals/resonators do you'll use?

2005-07-04 by Pigeon

Thanks for the reply!
I cannot find any 30pF for breadboarding..
I found 27pF:
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=338257&Row=256525&Site=US
and they carry 33pF:
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=338569&Row=256670&Site=US
What would be a better option? (So I assume all the crystals in my previous email would work with the same caps..)
thanks
Lee
----- Original Message -----
Sent: Sunday, July 03, 2005 11:55 PM
Subject: Re: [AVR-Chat] What crystals/resonators do you'll use?

At 10:03 PM 7/3/2005, Pigeon wrote:
Sounds good.

Just to double check (because I am about to make an order from digkey) (and my last order.. I had some wrongly ordered parts)


For the Caps, I would use:
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=328204&Row=415594&Site=US

Ah grasshopper, you have missed the calculation of the cap values.

C = 2CL - Cstray

C = (2*18)-6 Guessing at 5-6pF or thereabouts

C = 30pF

The reason for this, in short, is that from the crystal's point of view, the caps are in series.

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