[SI-LIST] Re: Guard Traces - Use 'Em, or Not?

  • From: Dudi Tash <dudi@xxxxxxxxxxxxxxxxx>
  • To: "bertsimonovich@xxxxxxxxxx" <bertsimonovich@xxxxxxxxxx>, "ken@xxxxxxxxxxxxxxxx" <ken@xxxxxxxxxxxxxxxx>, "EMC-PSTC@xxxxxxxxxxxxxxxxx" <EMC-PSTC@xxxxxxxxxxxxxxxxx>, 'SI-LIST' <si-list@xxxxxxxxxxxxx>
  • Date: Fri, 25 May 2012 10:55:22 +0300

Wow, great stuf...

Thanks a lot for sharing it.

Best Regards,
Dgtronix Ltd. I Founder & CEO I Dudi Tash 
eFax: +972-3-7256490 I Mobile: +972-54-6345629 I Office: +972-9-9660967
www.dgtronix-tech.com






*This email contains confidential and proprietary information of Dgtronix Ltd.*

-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On 
Behalf Of Lambert Simonovich
Sent: Friday, May 25, 2012 3:15 AM
To: ken@xxxxxxxxxxxxxxxx; EMC-PSTC@xxxxxxxxxxxxxxxxx; 'SI-LIST'
Subject: [SI-LIST] Re: Guard Traces - Use 'Em, or Not?

Ken et al,

Good blog post. I have been doing a little research myself; hopefully to put 
the subject to bed. I was putting the finishing touches on a white paper when 
you posted your link.

Abstract:
To guard or not to guard? That is the question often asked by digital hardware 
design engineers. As bit rates continue to climb, there is increased debate on 
whether to use guard traces to control crosstalk in high-speed digital 
signaling.  By doing so, it is believed the guard trace will act as a shield 
between the aggressor and victim traces.  On the other hand, the argument is 
that merely separating the victim trace to at least three times the line width 
from the aggressor is good enough.  This paper studies the application of guard 
traces and quantifies the results against non guarded scenarios.

Conclusions:
This study has shown that adding a guard trace, at 3 times the line width, 
terminated at both ends with 50 Ohms, does little to improve crosstalk on the 
victim. In fact, in most cases, it was worse. The same was true when the guard 
trace was grounded only at each end. But adding a ground-stitched guard trace, 
with the same spacing, showed it was the best solution for microstrip, and had 
little to no benefit for stripline. However, by increasing the spacing to 5 
times the line width in microstrip, the crosstalk, for all intensive purposes, 
was the same. In stripline, there was no benefit in adding a guard trace for 
digital signaling.

You can download a copy from my website. Hope everyone finds it useful. Here is 
the link:

http://bit.ly/KSM5BZ

Best regards,

Bert Simonovich, Consultant & Founder
LAMSIM Enterprises Inc.
"Innovative Signal Integrity and Backplane Solutions"
Email: lsimonovich_at_lamsimenterprises.com
Blog: http://blog.lamsimenterprises.com/
LinkedIN: http://www.linkedin.com/in/bertsimonovich
Web Site: http://lamsimenterprises.com/

=======================================================

-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On 
Behalf Of Ken Wyatt
Sent: May-24-12 2:43 PM
To: EMC-PSTC@xxxxxxxxxxxxxxxxx; SI-LIST
Subject: [SI-LIST] Guard Traces - Use 'Em, or Not?

Hi Group,
After noticing the continued banter and discussions regarding guard traces in 
both the EMC and SI groups over the past months, I decided to consult a couple 
experts on the subject - Howard Johnson and Eric Bogatin. I summarized their 
thoughts in my latest blog posting on the Test & Measurement World web site:
http://www.tmworld.com/blog/The_EMC_Blog/41806-Guard_Traces_Use_Em_or_Not_.p
hp. I invited both to add any additional comment, if they wished. Feel free to 
add to the discussion.

Cheers, Ken
_______________________
Kenneth Wyatt
Wyatt Technical Services LLC
Woodland Park, CO
Email Me! | Web Site | Blog
Subscribe to Newsletter
Connect with me on LinkedIn


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