[SI-LIST] : RE: [SI-LIST]: Spectraquest Vs. XTK/XNS

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From: Haller, Robert (rhaller@cereva.com)
Date: Fri Nov 10 2000 - 08:23:27 PST


Ken,
        You did a great job of summarizing the major
benefits and issues. I concur that SQ is an excellent
choice if you use Allegro for your PWB design.

Over the years I have spent an inordinate amount of time getting
tools to 'talk' to each other and debugging translation issues.
Definitely put thought in your Overall CAD Process flow !
 
As far as timing goes I find Blast (formerly Motive) is acceptable
(but has limitations). It is fairly easy to go from SQ into Blast.

My $0.02

Bob Haller
Cereva Networks
3 Network Drive
Marlboro MA. 01752
Phone: 508-486-9660 X 3365
FAX: 508-486-9661
Email: rhaller@cereva.com

-----Original Message-----
From: Ken Willis [mailto:Ken.Willis@sycamorenet.com]
Sent: Thursday, November 09, 2000 6:40 PM
To: si-list@silab.eng.sun.com
Subject: [SI-LIST] : RE: [SI-LIST]: Spectraquest Vs. XTK/XNS

Hi everyone,

The interconnect modeling capability of SQ is actually very
strong, with its frequency dependent lossy coupled TLine
functionality, a la W element. If you put in the right
loss tangent values for the materials you are using, you
can get very good agreement. I have gotten very good
eye pattern correlation up to data rates of 2.5 GHz, through
backplanes, connectors, etc. You have to do some extra effort
on via modeling (simple lumped via models don't work well at
those frequencies). But since SQ is spice-based, you can write
your own spice subcircuits for vias when you get to those
frequencies. The spice-based nature allows you to model all
kinds of detailed stuff very well.

But SQ is definitely a toolset for people using Allegro as the
back end. There is some loose integration to import PADS
and Mentor databases, but I don't see this as the strength at all.
The integration with Allegro is a huge plus, and the ability to
quickly extract a graphical electrical topology is something
I use daily, and find invaluable for troubleshooting. It is
also pretty easy to hook multiple (Allegro) databases together
and do massive batch simulations. I have now simulated well over
a dozen complete (big) designs and we have had very good lab
correlation, and caught lots of stuff before going to fab.

On the negative side, documentation is weak compared
to HL or XTK, and the support/training can vary a lot. But if your
company uses an Allegro back end and you know what you are doing,
SQ can be a lifesaver if you need to do industrial-strength levels
of analysis. There is also huge potential to enable
formal constraint-driven design downstream in Allegro, which I
think is largely untapped at this point.

Ken Willis
Sycamore Networks

-----Original Message-----
From: Ken Cantrell [mailto:Ken.Cantrell@srccomp.com]
Sent: Thursday, November 09, 2000 4:05 PM
To: Todd Westerhoff; si-list
Subject: RE: [SI-LIST] : RE: [SI-LIST]: Spectraquest Vs. XTK/XNS

Re: Todd's 2 cents,
I would add that if you are in a large product line environment (on stop
shopping), SpectraQuest is great with it's global auto-update features,
saves you significant time. I thought their interconnect modeling was
weak
though, and their timing analysis depended on your already knowing your
timing margins. Have they updated those features?
Ken

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