PCB design advice needed

Dec 06, 2006 4 Replies
R

Just finishing a fairly simple board (2 layer board) and find that I have a fairly large area (relative to the board size) of unconnected copper copper zones/polygons on both sides of the board.



I thought it was a good idea to leave these unused areas of copper since it should make manufacturing quicker since less copper needs to be etched away.



However, what is the rule of thumb in regards to this? Could the two areas of unconnected copper cause some unpleasant effects, work as an antenna or behave like a capacitor?



Any advice?



Thanks.


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J

...not to mention environmental impact.

http://66.102.9.104/search?q=cache:wZ772MGFYPIJ:

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(Depending on the dimensions of the board, mechanical stresses might be a bigger concern.)

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P

http://66.102.9.104/search?q=cache:wZ772MGFYPIJ:

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It is common for board fabricators to fill unused zones with copper to relieve mechanical stress. It can certainly add problems by radiating signals, but it depends on the board.

Many times, the added copper is small squares - large enough to minimise mechanical stress and not large enough (for low speed boards) to act as antennae.

On high speed boards, I fill unused areas with copper and stitch them thoroughly to ground.

Cheers

PeteS

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S

On 2-layer boards, I usually connect them to ground on one side, and another supply on the other and get a free capacitor along with the shielding.

I don't think there is any detectable price difference between all copper and none..

Best regards, Spehro Pefhany

"it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
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C

http://66.102.9.104/search?q=cache:wZ772MGFYPIJ:

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The terminology for this is "copper balancing". Hopefully google will be your friend.

Colin

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