[SI-LIST] Re: ground planes at top / bottom layer
- From: "Kenneth W. Egan" <kegan@xxxxxxxxxxxxx>
- To: <si-list@xxxxxxxxxxxxx>
- Date: Fri, 2 Jan 2009 20:39:16 -0600
True enough. However, someone really did F&*K up the thermals, and poor
power supply design. I went through 3 of the original xbox's due these well
documented issues.
KWE
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On
Behalf Of Lee Ritchey
Sent: Friday, January 02, 2009 5:33 PM
To: earl albin; si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: ground planes at top / bottom layer
No, the Xbox did not start at 6 layers. Why do I know this? I helped in
the design. It is not alone. Tens of millions of PC motherboards are
designed the same way.
Some of these replies sound like defending poor engineering methods.
Better to learn the correct engineering methods and save you companies some
valuable development costs.
Lee Ritchey
> [Original Message]
> From: earl albin <earlalbin@xxxxxxxxx>
> To: <si-list@xxxxxxxxxxxxx>
> Date: 1/2/2009 12:45:36 PM
> Subject: [SI-LIST] Re: ground planes at top / bottom layer
>
> Lee:
> The Sun rises in the East and sets in the West. "ground layers on the
> outside of PCBs to control EMI", East-West thing here.
>
> "Xbox didn't do it and it passes," ok, yes. Obviously their four layer
board
> had enough margin. Likely as well they started with a six layer solution
> (safe), added up the cost (consumer vs profit) made appropriate changes
and
> they pass with a four layer. Six layers in not the only tool in your tool
> box, many ways to skin the cat, etc...
>
> If you don't own an Xbox and you haven't torn it apart, why, if your goal
is
> similar. I hope you have the time to gain a critical understanding of what
> Xbox did, mostly though why, they did what they did.
>
----------------------------------------------------------------------------
------------------------------------------------------
> To all of those who recommend ground layers on the outside of PCBs to
> control EMI, take a look at a PC mother board or the motherboard in the
> Xbox. They are 4 layer PCBs that have signals on both outside layers and
> the products in which they are shipped pass EMI standards.
>
> Where did the notion that outer layers had to be ground in order to pass
> EMI come from? My guess is it is an RE.
>
> Lee Ritchey
>
----------------------------------------------------------------------------
------------------------------------------------------
>
>
> ------------------------------------------------------------------
> 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
>
------------------------------------------------------------------
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
------------------------------------------------------------------
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:
