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shadders
United Kingdom
224 Posts |
 Posted - 08 Sep 2010 : 08:55:45
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Hi,
In applying copper fill areas, i have a number of isolated copper filled areas. The larger fill areas i have used a Via to connect to the power plane/copper layer below the filled area.
For others, there is no connection to the equivalent Net directly below - as this may be the wrong plane.
Hence, leaving the isolated copper fill areas unconnected to another voltage potential such as ground, will produce a capacitor.
Is this a problem ?. Can a voltage build up on these areas ?.
I assume best practice is to remove such isolated copper fills ?.
Thanks and regards,
Richard. |
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Iain Wilkie
United Kingdom
1015 Posts |
Posted - 08 Sep 2010 : 11:17:00
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Richard,
I have always done the pour to remove these isolated areas. Generally yes it is bad practice to have floating copper areas.
Iain |
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shadders
United Kingdom
224 Posts |
Posted - 08 Sep 2010 : 11:38:25
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Hi Iain,
Thanks.
Regards,
Richard. |
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shadders
United Kingdom
224 Posts |
Posted - 08 Sep 2010 : 14:23:07
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Hi,
Thinking about the voltage build up - don't think this is possible - since there is no connection to supply excess or deplete the electrons in the copper shape.
It may act as a capacitive coupling but i don't think a voltage can appear permanently.
Regards,
Richard. |
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Iain Wilkie
United Kingdom
1015 Posts |
Posted - 08 Sep 2010 : 15:30:13
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If floating copper is seperating tracks , it can couple these togerther. Also they can act as antenna.
We did a lot of work for a radio application client and they insisted that there be no floating copper !
Iain
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shadders
United Kingdom
224 Posts |
Posted - 08 Sep 2010 : 16:03:11
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Hi Iain,
Thanks - i did a quick calculation using basic capacitance formula - a few mm^2 has a reasonable pF value - which as you have stated is an antenna issue.
Regards,
Richard. |
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Topic |
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Isolated Copper Fill Areas