[SI-LIST] Re: High speed signal-return path

That makes sense for DC current, but the point is that the power and
ground planes are shorted together in the RF sense by a properly
implemented bypass network.  Therefore, one is as good as the other for
RF.  RF energy never reaches the power supply -- if it does, something is
very wrong.
Orin

On Sat, 22 Sep 2007 22:11:06 -0700 (PDT) Jory McKinley
<jory_mckinley@xxxxxxxxx> writes:
Hello Orin,
There is in that the return current has to do just that, return.  So for
single ended or common mode differential sourcing or sinking from power
or ground could make a significant difference, somewhat regardless of
edge rate.  All mute for ideal differential of coarse.
-Jory




----- Original Message ----
From: "olaney@xxxxxxxx" <olaney@xxxxxxxx>
To: jory_mckinley@xxxxxxxxx
Cc: raja.anand@xxxxxxxxx; si-list@xxxxxxxxxxxxx
Sent: Saturday, September 22, 2007 12:49:27 PM
Subject: [SI-LIST] Re: High speed signal-return path


We all know differential versus single ended, but "return current plane,
not ground" needs explanation if you feel that there is some nontrivial
difference at high frequencies between power and ground planes.
Orin

On Sat, 22 Sep 2007 10:36:14 -0700 (PDT) Jory McKinley
<jory_mckinley@xxxxxxxxx> writes:
Yes, however every plane is a potential return current plane, not ground,
less important for true differential more important for single ended. 
How about any common mode noise on the differential signals, I would
think Option 1 would allow for better potential isolation.
-Jory




----- Original Message ----
From: "olaney@xxxxxxxx" <olaney@xxxxxxxx>
To: raja.anand@xxxxxxxxx
Cc: si-list@xxxxxxxxxxxxx
Sent: Saturday, September 22, 2007 6:51:30 AM
Subject: [SI-LIST] Re: High speed signal-return path


Every power plane is a ground plane for high frequency purposes.  There
should be no material difference between the two implementations.  If
there is, something is really wrong with the power supply bypassing
strategy.  The choice between stripline and microstrip is generally
driven by the particulars of the board layout.  There is no definitive
choice of one over the other based on general principles, only as
circumstances dictate.

Orin Laney

On Sat, 22 Sep 2007 11:12:19 +0530 "Raja Anand" <raja.anand@xxxxxxxxx>
writes:
> Hi All,
>  For high speed differential signals (3.125Gbps ), is it really 
> required to
> take these signals between Gnd Planes.  Which option should I go for 
> from
> below if my stack up is symmetrical?
> 
>  Option1:
> L4 - Power
> L5 - Signal
> L6 ? GND
> 
>  Option2:
> L4 - GND
> L5 - Signal
> L6 ? GND
> 
> Regards,
> Raja
> 
> ------------------------------------------------------------------
> 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:
> http://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:     
>                 http://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:
http://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:     
        http://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
  







Check out the hottest 2008 models today at Yahoo! Autos. 

------------------------------------------------------------------
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:
http://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:     
        http://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
  







Take the Internet to Go: Yahoo!Go puts the Internet in your pocket: mail,
news, photos & more. 

------------------------------------------------------------------
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:
http://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:     
                http://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: