dead copper on pcb polygone plane

Peter Verkaik

Hi,
I designed a two-layer pcb and added a ploygone plane on both component
and solder side. The top plane connects to VDD and the bottom plane
connects to GND.
Is it wise to leave dead copper areas in place or should I remove these?

regards peter

Bean

Peter,
They would act as a bypass capacitor, so I would think it would be better to leave them.
G

Peter Verkaik

Wouldn't dead copper between two signal tracks increase
any possible signal degradation? A ground or VDD plane
would decouple two signals, but how about dead copper?

regards peter

nick bernard

a little google research implies that its a bad thing.

dead copper removal is an important issue specially for designing highly populated, only-SMD boards. @ http://www.geda.seul.org/mailinglist/geda-user17/msg00105.html

It is considered a "bad thing" to have dead copper in your PCB @ http://groups.google.com/group/sci.electronics.design/browse_thread/thread/1b02ab3a0bcc1daa/ae6e8041f64e0255#ae6e8041f64e0255

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engineer, fireman, bowler, father, WoW addict [noparse];)[/noparse]

Chris Savage

Peter,

·· I'm sure you already thought of this, but unless your mounting holes are isolated from the planes, if you use a metal screw through the PCB it·could short both planes.· This is especially true if you're mounting to standoffs.

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Chris Savage
Parallax Tech Support
csavage@parallax.com

Peter Verkaik

nick,
Thanks for the links.
I will connect any dead copper manually or remove it.

Chris,
my mounting holes are actually plated through holes of 4mm
which do not connect to anything.
regards peter

·

Peter Verkaik

One more question:
What is 'the best' density for polygon planes?
I currently have a 50% fill (20 mil grid with 10 mil tracks)
Clearance between polygone and tracks/pads is 15 mil.
See attachement.

regards peter