[SI-LIST] Re: EXT :Re: What's the purpose of stitching vias whichjust connect one GND layer?

  • From: Douglas Smith <doug@xxxxxxxxxx>
  • To: Scott McMorrow <scott@xxxxxxxxxxxxx>
  • Date: Sat, 07 Nov 2015 21:00:47 -0500

Hi Steve,
How about sitting in on the GoTMeeting session to see what I did? Should be easy
to model as there are only two traces on the board.
Doug Smith Sent from my iPhone IPhone: 408-858-4528 [tel:408-858-4528] Office:
702-570-6108 [tel:702-570-6108] Email: doug@xxxxxxxxxx Website:
http://dsmith.org

On Sat, Nov 7, 2015 at 20:41, Scott McMorrow <scott@xxxxxxxxxxxxx> wrote:
Doug,
they are stitching vias, and accomplish the same effect. We should be able to
model your test board, quite easily and show correlation of modeling to
measurements.
In most real board, there are a huge number of ground vias, stitching the
planes, since every device has grounds. It is those left out nether regions of a
PCB where the type of issues you demonstrate can occur. Where there are not
parts, no ground stitch vias, and open signal routing through vias.
Scott



logo-02.png [http://teraspeed.com/images/logo-02.png]


Scott McMorrow R&D Consultant Teraspeed Consulting - A Division of Samtec 16
Stormy Brook Rd
Falmouth, ME 04105
(401) 284-1827 Business
[http://www.teraspeed.com] http://www.teraspeed.com [http://www.teraspeed.com]
On Sat, Nov 7, 2015 at 8:34 PM, Douglas Smith < doug@xxxxxxxxxx
[doug@xxxxxxxxxx] > wrote:
No. I mean of course gnd layer to gnd layer vias to short out the z axis plane
to plane impedance at a signal via. That may be different than the stitching
vias discussed earlier, but I call these stitching vias as well.

Doug Smith Sent from my iPhone IPhone: 408-858-4528 Office: 702-570-6108 Email:
doug@xxxxxxxxxx [doug@xxxxxxxxxx] Website: [http://dsmith.org]
http://dsmith.org [http://dsmith.org]

On Sat, Nov 7, 2015 at 20:20, Lee Ritchey < leeritchey@xxxxxxxxxxxxx
[leeritchey@xxxxxxxxxxxxx] > wrote:
Do you realize how nebulous that sounds?

-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [si-list-bounce@xxxxxxxxxxxxx] [mailto:
si-list-bounce@xxxxxxxxxxxxx [si-list-bounce@xxxxxxxxxxxxx] ] On Behalf Of
Douglas Smith
Sent: Saturday, November 7, 2015 5:27 AM
To: Lee Ritchey < leeritchey@xxxxxxxxxxxxx [leeritchey@xxxxxxxxxxxxx] >
Cc: chris.cheng@xxxxxxx [chris.cheng@xxxxxxx] ; Scott McMorrow <
scott@xxxxxxxxxxxxx [scott@xxxxxxxxxxxxx] >; Shimko, Steve (ES\) <
s.shimko@xxxxxxx [s.shimko@xxxxxxx] >; istvan.novak@xxxxxxxxxxx
[istvan.novak@xxxxxxxxxxx] ; dmarc-noreply@xxxxxxxxxxxxx
[dmarc-noreply@xxxxxxxxxxxxx] ; si-list@xxxxxxxxxxxxx [si-list@xxxxxxxxxxxxx] ;
bbakshan@xxxxxxxxx [bbakshan@xxxxxxxxx] ; Kevin.Hou@xxxxxxxxxx
[Kevin.Hou@xxxxxxxxxx]
Subject: [SI-LIST] Re: EXT :Re: What's the purpose of stitching vias whichjust
connect one GND layer?

Just to be clear, I was speaking of single or a few vias at places where a
signal changes many layers on a PCB, not for crosstalk control. The purpose is
to keep down emissions or increase immunity on a PCB.
Doug Smith Sent from my iPhone IPhone: 408-858-4528 [tel:408-858-4528] Office:
702-570-6108 [tel:702-570-6108] Email: doug@xxxxxxxxxx [doug@xxxxxxxxxx]
Website: [http://dsmith.org] http://dsmith.org [http://dsmith.org]

On Fri, Nov 6, 2015 at 19:08, Lee Ritchey < leeritchey@xxxxxxxxxxxxx
[leeritchey@xxxxxxxxxxxxx] > wrote:
Chris,

Well put!

-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [si-list-bounce@xxxxxxxxxxxxx] [mailto:
si-list-bounce@xxxxxxxxxxxxx [si-list-bounce@xxxxxxxxxxxxx] ] On Behalf Of
Cheng, Chris
Sent: Thursday, November 5, 2015 12:51 PM
To: doug@xxxxxxxxxx [doug@xxxxxxxxxx] ; Scott McMorrow < scott@xxxxxxxxxxxxx
[scott@xxxxxxxxxxxxx] >; Shimko, Steve (ES) < s.shimko@xxxxxxx
[s.shimko@xxxxxxx] >
Cc: Lee Ritchey < leeritchey@xxxxxxxxxxxxx [leeritchey@xxxxxxxxxxxxx] >;
istvan.novak@xxxxxxxxxxx [istvan.novak@xxxxxxxxxxx] ;
dmarc-noreply@xxxxxxxxxxxxx [dmarc-noreply@xxxxxxxxxxxxx] ;
si-list@xxxxxxxxxxxxx [si-list@xxxxxxxxxxxxx] ; bbakshan@xxxxxxxxx
[bbakshan@xxxxxxxxx] ; Kevin.Hou@xxxxxxxxxx [Kevin.Hou@xxxxxxxxxx]
Subject: [SI-LIST] Re: EXT :Re: What's the purpose of stitching vias whichjust
connect one GND layer?

Must have VIAs------Steve
No VIAs for you ------ Lee
Chris Cheng
Distinguished Technologist , Electrical
Hewlett-Packard Enterprise Company

+1 510 344 4439/ Tel
chris.cheng@xxxxxxx [chris.cheng@xxxxxxx] / Email
4209 Technology Dr
Fremont, CA 94538
USA



-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [si-list-bounce@xxxxxxxxxxxxx] [mailto:
si-list-bounce@xxxxxxxxxxxxx [si-list-bounce@xxxxxxxxxxxxx] ] On Behalf Of Doug
Smith
Sent: Thursday, November 05, 2015 11:58 AM
To: Scott McMorrow; Shimko, Steve (ES)
Cc: Lee Ritchey; istvan.novak@xxxxxxxxxxx [istvan.novak@xxxxxxxxxxx] ;
dmarc-noreply@xxxxxxxxxxxxx [dmarc-noreply@xxxxxxxxxxxxx] ;
si-list@xxxxxxxxxxxxx [si-list@xxxxxxxxxxxxx] ; bbakshan@xxxxxxxxx
[bbakshan@xxxxxxxxx] ; Kevin.Hou@xxxxxxxxxx [Kevin.Hou@xxxxxxxxxx]
Subject: [SI-LIST] Re: EXT :Re: What's the purpose of stitching vias whichjust
connect one GND layer?

Can someone translate the characters below for me?

Doug
University of Oxford
Department for Continuing Education
Oxford, Oxfordshire, United Kingdom
--------------------------------------------------
Doug Smith
P.O. Box 60941
Boulder City, NV 89006-0941
TEL/FAX: 702-570-6108/570-6013
Mobile: 408-858-4528
Email: doug@xxxxxxxxxx [doug@xxxxxxxxxx]
Web: [http://www.dsmith.org] http://www.dsmith.org [http://www.dsmith.org]
--------------------------------------------------


On Thu, 5 Nov 2015 19:45:03 +0000, "Shimko, Steve (ES)"
< s.shimko@xxxxxxx [s.shimko@xxxxxxx] > wrote:
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