[SI-LIST] Re: risetime effects of plane breaks
- From: Chris Padilla <cpad@xxxxxxxxx>
- To: SI-List <si-list@xxxxxxxxxxxxx>
- Date: Mon, 10 Jan 2005 19:20:01 -0800
I'd like to see the EMI implications (radiation) of crossing a split in a
plane. What is okay for SI may not be so for EMI....
----->Chris
At 07:05 PM 1/10/2005 -0800, Chris Cheng wrote:
>I see, but I will be more interested in real life application where there is
>a stripline crossing a cut power plane with a solid ground on the other
>side. They exit in really world and I for one would like to know at what
>point it will degrade the performance to an unacceptable level. 300ps edge ?
>100ps edge ? 20 mil gap ? 100 mil gap ? etc. My experience suggest they can
>work up to a reasonable speed (at least to the point where you start
>thinking maybe differential signal makes more sense due to other design
>considerations).
>
>-----Original Message-----
>From: steve weir [mailto:weirsp@xxxxxxxxxx]
>Sent: Monday, January 10, 2005 6:56 PM
>To: Chris.Cheng@xxxxxxxxxxxx; SI-List
>Subject: Re: [SI-LIST] Re: risetime effects of plane breaks
>
>
>Chris, because Zontar is listening.
>
>Doug set-up a nice physics experiment that nicely demonstrates the bad
>things that happen when crossing a split with no other solid plane in the
>vicinity. For my money, it aptly demonstrates several important effects
>and precisely why it would be a bad idea to put into practice.
>
>Various people from Lee to Dan, Arpad, and yourself have pointed-out that
>under appropriate circumstances crossing a cut is not automatically the end
>of the world. I don't think anyone proposes that crossing cuts like Doug
>has set-up comes without substantial consequences.
>
>Best Regards,
>
>
>Steve.
>
>At 06:30 PM 1/10/2005 -0800, Chris Cheng wrote:
> >Sorry but I have to ask, why would anyone will run a single edge signal at
> >300ps as microstrip across a cut ground reference plane ? I can understand
> >if it is a stripline with a solid ground on one reference and cut power
> >planes on the other (which I have do a lot, not by choice though). What
> >application will call for such routing ?
> >
> >-----Original Message-----
> >From: steve weir [mailto:weirsp@xxxxxxxxxx]
> >Sent: Monday, January 10, 2005 12:28 PM
> >To: arpad.muranyi@xxxxxxxxx; SI-List
> >Subject: [SI-LIST] Re: risetime effects of plane breaks
> >
> >
> >Arpad, a jump from 10-14% coupling up to 30% or so is still very
> >significant. Phase match and other common mode issues should not be
> >dismissed when attempting to cross a split. The first choice should be
> >don't do it. But if one must, then do so with care.
> >
> >Regards,
> >
> >
> >Steve.
> >At 11:41 AM 1/10/2005 -0800, Muranyi, Arpad wrote:
> > >Even though I was just speed reading this
> > >thread, I didn't see this mentioned yet:
> > >
> > >You can also get by with plane breaks if the
> > >traces going over it are closely coupled
> > >differential pairs...
> > >
> > >Arpad
> >
> >=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> >=
> > >=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=20
> > >
> > >-----Original Message-----
> > >From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
>=
> > >On Behalf Of steve weir
> > >Sent: Monday, January 10, 2005 11:21 AM
> > >To: emcesd2000@xxxxxxxxx; SI-List
> > >Subject: [SI-LIST] Re: risetime effects of plane breaks
> > >
> > >Oscar, yes, it is quite a dramatic effect isn't it? I suspect that =
> > >when=20
> > >Lee says "it depends on how you do it" he has another contiguous plane, =
> > >ie=20
> > >ground underneath the split as opposed to a split on all planes as in=20
> > >Doug's experiment. Assuming lots of decoupling between each of the =
> > >islands=20
> > >and the common ground plane the jump in coupling between lines would be
>=
> > >
> > >greatly suppressed.
> > >
> > >Regards,
> > >
> > >
> > >Steve.
> > >
> > >At 11:00 AM 1/10/2005 -0800, Ahmad Fallah wrote:
> > > >Hi Steve,
> > > >
> > > >I have repeated Doug's experiment with a modified fixture where an=20
> > > >additional trace (victim) was added near (~1 cm) the "signal" line
>for=20
> > > >X-talk measurements. I have measured a 10-fold increase in x-talk=20
> > > >amplitude in going from Case 1 to Case 2.
> > > >
> > > >Case 1: the offending and victim lines are both drawn over a solid =
> > >return=20
> > > >plane.
> > > >Case 2: the offending and victim lines are both drawn over the cut in =
> > >the=20
> > > >return plane
> > > >
> > > >Regards,
> > > >
> > > >Oscar
> > > >
> > > >
> > > >
> > > >steve weir <weirsp@xxxxxxxxxx> wrote:
> > > >
> > > >Lee, the 5cm is the length of the break. The break is only about =
> > >20-50mils
> > > >wide. Hit the link and scroll to Figure 3. In Doug's test set-up, both
>=
> > >of
> > > >the two planes have been broken. Now, If one cares to do a crosstalk =
> > >test,
> > > >it looks like Doug could modify his fixture rather easily to do that. =
> > >In
> > > >the vicinity of the break, the multiple line coupling, including =
> > >between
> > > >members of a diff pair jumps.
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >If you want to perform an entertaining experiment, take a diff pair, or
> > > >just one active driver and a quiet line and route them over a narrow, =
> > >and
> > > >short break, say 0.25" by 0.02" and take four port S parameter
> > > >measurements. Take another pair and do likewise, but keep extending the
> > > >length of the slot, ie perpendicular to the traces by a factor of 2 =
> > >with
> > > >each test. Even though the width of the gap is short, by the time that
> > > >slot becomes an inch or two long the band of frequencies where coupling
>=
> > >is
> > > >fairly strong will be pretty wide.
> > > >
> > > >http://emcesd.com/tt2005/tt010105.htm
> > > >
> > > >Regards,
> > > >
> > > >Steve
> > > >
> > > >
> > > >At 04:30 PM 1/9/2005 -0800, Lee Ritchey wrote:
> > > > >Just noticed that you call a 5 cm break relatively small. Does that =
> > >mean
> > > > >5 cm in width?
> > > > >
> > > > >Lee W. Ritchey
> > > > >Speeding Edge
> > > > >P. O. Box 2194
> > > > >Glen Ellen, CA 95442
> > > > >Phone- 707-568-3983
> > > > >FAX- 707-568-3504
> > > > >
> > > > >I just used the energy it took to be angry to write some blues.
> > > > >Count Basie
> > > > >
> > > > >
> > > > > > [Original Message]
> > > > > > From: Doug Smith
> > > > > > To: SI-List
> > > > > > Date: 1/8/2005 5:23:26 PM
> > > > > > Subject: [SI-LIST] risetime effects of plane breaks
> > > > > >
> > > > > > I think most of us know not to route signals over plane breaks on
>=
> > >PWBs
> > > > > > as all kinds of bad things can happen when this occurs in a =
> > >layout.
> > > > > > But, how do you convince co-workers or your boss that a new design
> > > > > > needs to avoid doing this even if added expense or project delay =
> > >is
> > > > > > required? Experimental data can be the key and this month my =
> > >Technical
> > > > > > Tidbit shows what happens to signal risetime if the signal crosses
>=
> > >a
> > > > > > plane break.
> > > > > >
> > > > > > Crossing Ground Plane Breaks - Part 4
> > > > > > Risetime Effects on Signals
> > > > > >
> > > > > > Abstract: Signals that cross ground plane breaks on printed wiring
> > > > > > boards (PWBs) experience degradation as well as cause EMI =
> > >problems.
> > > > > > Significant degradation of signal risetime is shown to occur, even
> > > > > > with a relatively small ground break of five cm at risetimes on =
> > >the
> > > > > > order of 300 ps.
> > > > > >
> > > > > > The link to the article is the picture of the experimental test =
> > >setup
> > > > > > at the bottom of the home page at http://emcesd.com .
> > > > > >
> > > > > > Doug
> > > > > > --
> > > > > > -------------------------------------------------------
> > > > > > ___ _ Doug Smith
> > > > > > \ / ) P.O. Box 1457
> > > > > > =3D=3D=3D=3D=3D=3D=3D=3D=3D Los Gatos, CA 95031-1457
> > > > > > _ / \ / \ _ TEL/FAX: 408-356-4186/358-3799
> > > > > > / /\ \ ] / /\ \ Mobile: 408-858-4528
> > > > > > | q-----( ) | o | Email: doug@xxxxxxxxxx
> > > > > > \ _ / ] \ _ / Website: http://www.dsmith.org
> > > > > > -------------------------------------------------------
> > > > > >
> > > > > > ------------------------------------------------------------------
> > > > > > 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 FAQ wiki page is located at:
> > > > > > http://si-list.org/wiki/wiki.pl?Si-List_FAQ
> > > > > >
> > > > > > List technical documents are available at:
> > > > > > http://www.si-list.org
> > > > > >
> > > > > > 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 FAQ wiki page is located at:
> > > > > http://si-list.org/wiki/wiki.pl?Si-List_FAQ
> > > > >
> > > > >List technical documents are available at:
> > > > > http://www.si-list.org
> > > > >
> > > > >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 FAQ wiki page is located at:
> > > >http://si-list.org/wiki/wiki.pl?Si-List_FAQ
> > > >
> > > >List technical documents are available at:
> > > >http://www.si-list.org
> > > >
> > > >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 FAQ wiki page is located at:
> > > > http://si-list.org/wiki/wiki.pl?Si-List_FAQ
> > > >
> > > >List technical documents are available at:
> > > > http://www.si-list.org
> > > >
> > > >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 FAQ wiki page is located at:
> > > http://si-list.org/wiki/wiki.pl?Si-List_FAQ
> > >
> > >List technical documents are available at:
> > > http://www.si-list.org
> > >
> > >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
> > >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 FAQ wiki page is located at:
> > > http://si-list.org/wiki/wiki.pl?Si-List_FAQ
> > >
> > >List technical documents are available at:
> > > http://www.si-list.org
> > >
> > >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 FAQ wiki page is located at:
> > http://si-list.org/wiki/wiki.pl?Si-List_FAQ
> >
> >List technical documents are available at:
> > http://www.si-list.org
> >
> >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 FAQ wiki page is located at:
> > http://si-list.org/wiki/wiki.pl?Si-List_FAQ
> >
> >List technical documents are available at:
> > http://www.si-list.org
> >
> >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 FAQ wiki page is located at:
> http://si-list.org/wiki/wiki.pl?Si-List_FAQ
>
>List technical documents are available at:
> http://www.si-list.org
>
>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 FAQ wiki page is located at:
http://si-list.org/wiki/wiki.pl?Si-List_FAQ
List technical documents are available at:
http://www.si-list.org
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:
