[SI-LIST] Re: ground planes at top / bottom layer
- From: olaney@xxxxxxxx
- To: bernd.schuster12@xxxxxxxxxxxxxx
- Date: Tue, 30 Dec 2008 14:55:19 -0800
Outside ground planes are a classic means of controlling EMI from the
board proper, among other benefits. However they are certainly in the
way if you are probing traces for debug. The Atmel evaluation boards are
designed for probing and to keep cost low, so are no guide to what should
be done for your project. Of course, adding outside planes changes the
impedance calculations for traces underneath. Also, I would never use an
outer plane for VCC or anything other than ground. To do so begs for
disaster.
Regards,
Orin Laney
On Tue, 30 Dec 2008 21:24:26 +0100 "bernd schuster"
<bernd.schuster12@xxxxxxxxxxxxxx> writes:
> Hi,
> I`ve one small question about the usage of ground planes at the top
> and
> bottom layer. I thought it would be great to use them, but the atmel
> evaluation boards (for example) do not use an ground plane on the
> top layer
> or bottom layer. They use for example an 8 layer stack design (where
> layer 5
> is a vcc plane and layer 2 is a ground plane).
>
> Are there any disadvantages of using ground planes at the top /
> bottom
> layer? In my first 4-layer board I use ground planes at the top,
> bottom and
> at the second layer. I connect them with a lot of vias.
>
>
> best regards
> Bernd
>
>
> ------------------------------------------------------------------
> To unsubscribe from si-list:
> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject
> field
>
> or to administer your membership from a web page, go to:
> //www.freelists.org/webpage/si-list
>
> For help:
> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>
>
> List technical documents are available at:
> http://www.si-list.net
>
> List archives are viewable at:
> //www.freelists.org/archives/si-list
> or at our remote archives:
> http://groups.yahoo.com/group/si-list/messages
> Old (prior to June 6, 2001) list archives are viewable at:
> http://www.qsl.net/wb6tpu
>
>
>
>
____________________________________________________________
Smell Sexy! Top Perfumes. Click Now.
http://thirdpartyoffers.juno.com/TGL2141/fc/PnY6rw2rDgp94HXnN2wXj92qRDrysvEXs1VoaLSjWrak1sZIglSZx/
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List technical documents are available at:
http://www.si-list.net
List archives are viewable at:
//www.freelists.org/archives/si-list
or at our remote archives:
http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
