Jeff, I am aware there has been lots of discussion and that's just what it is. There is also plenty of science that supports my statements. It is true that whatever ripple there is on Vcc or Vdd will couple onto any signal that runs over that plane. Nothing wrong with that as long as the ripple voltage is within limits. This condition is satisfied by doing a good job of designing the power supply system. I've designed hundreds of supercomputer PCBs just this way. Does Cray Research ring a bell? How about Amdahl? Lee > [Original Message] > From: Loyer, Jeff <jeff.loyer@xxxxxxxxx> > To: Zhangkun <zhang_kun@xxxxxxxxxx> > Cc: <leeritchey@xxxxxxxxxxxxx>; si-list <si-list@xxxxxxxxxxxxx> > Date: 9/8/2003 8:53:20 AM > Subject: [SI-LIST] Re: Reference Plane > > Eeks! I would not agree with Lee's statement. There has been a LOT of = > discussion on this issue, and I would strongly suggest you work to = > understand the issues as they can have considerable impact. > > Searching through the archives for "reference plane" should give you = > tons of information on the subject. > > Jeff Loyer > > -----Original Message----- > From: Lee Ritchey [mailto:leeritchey@xxxxxxxxxxxxx] > Sent: Monday, September 08, 2003 8:08 AM > To: Zhangkun; si-list > Subject: [SI-LIST] Re: Reference Plane > > > Zhangkun, > > If you have designed your power subsystem correctly, the Vcc and ground > planes of you power supply will be tied to each other through less than = > 10 > milliohms at all of the frequencies that are in you signal, so you don't > haveto worry about a disconnect. > > Lee > > > > [Original Message] > > From: Zhangkun <zhang_kun@xxxxxxxxxx> > > To: si-list <si-list@xxxxxxxxxxxxx> > > Date: 9/8/2003 9:50:26 PM > > Subject: [SI-LIST] Reference Plane > > > > Dear All: > > There are one driver and one receiver, which is connected by one = > trace. > The driver and receiver use GND as their reference. The trace use VCC as > its reference plane. As shown in power integrity, there is impedance > between power and ground. Therefore, there are one disconnection at the > driver and one disconnection at the receiver. Would these two = > disconnection > disgrade signal integrity? > > > > Best Regards > > > > Zhangkun > > 2003.09.08 > > > > > > ------------------------------------------------------------------ > > 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 archives are viewable at: =20 > > //www.freelists.org/archives/si-list > > or at our remote archives: > > http://groups.yahoo.com/group/si-list/messages=20 > > Old (prior to June 6, 2001) list archives are viewable at: > > http://www.qsl.net/wb6tpu > > =20 > > > > ------------------------------------------------------------------ > 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 archives are viewable at: =20 > //www.freelists.org/archives/si-list > or at our remote archives: > http://groups.yahoo.com/group/si-list/messages=20 > Old (prior to June 6, 2001) list archives are viewable at: > http://www.qsl.net/wb6tpu > =20 > > ------------------------------------------------------------------ > 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 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 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