Re: [SI-LIST] : Copper pour beneath oscillators,

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From: David Bengtson (dbengtson@pobox.com)
Date: Wed Jun 06 2001 - 03:19:27 PDT


Putting on my RF engineering hat, I will say that copper pours over
the entire board are evil tools of the devil. You are increasing your
parasitic capacitance in an "uncontrolled" fashion.

Speaking for the oscillator, putting copper under it will increase the
parasitic capicitance, potentially coupling noise into and out of the
oscillator.

Dave

On Tue, 5 Jun 2001 10:23:39 +0500, you wrote:

>Hi,
> I'm a novice and my question might sound stupid but nontheless its a question to me. I'm desiging a board with 20 Mhz clock oscillators on it, i have put copper pour on the vacant areas of the board and connected the copper to the ground (common to all components), this copper also extends beneath the oscillators. The designer of the circuit is not happy with it and says that it will inflict all the noise generated by other components onto the oscillators output and rather he suggests that copper beneath the oscillators should remain unconnected this way any noise inflicted on or by the oscillator will remain isolated and not cause any problems. Can anyone please explain as it is a little confusing for me.
> Thanx in advance,
> Shoaib

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