RE: [SI-LIST] : Linpar 2-D field solver experiences?

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From: Larry Miller (ldmiller@nortelnetworks.com)
Date: Fri Dec 01 2000 - 07:39:32 PST


Thanks for the large number of replies I got. Sort of reminded me of the old
Dean Martin show, or even earlier (1950's) the Stan Freberg satire of
Lawrence Welk:

Thanks, for all those cards and letters
From all you folks out there in Television-land
I wonder where this Television-land is;
Maybe a couple of miles from where Disney-land is....

Those of you old enough (probably about 1%) will recall that "land" was
pronounced "Lendt". The record was "Wunnerful-a-Wunnerful"

Anyway, thanks again. I think I can find LinPar!!!!

Larry Miller

> -----Original Message-----
> From: Scott McMorrow [SMTP:scott@vasthorizons.com]
> Sent: Thursday, November 30, 2000 2:13 PM
> To: Miller, Larry [SC7:322:EXCH]
> Cc: MikonCons@aol.com; si-list@silab.eng.sun.com
> Subject: Re: [SI-LIST] : Linpar 2-D field solver experiences?
>
> Larry,
>
> LINPAR and MULTLIN are available from Artech House www.artechhouse.com
> <http://www.artechhouse.com>
> and from Amazon:
>
> LINPAR $375
> <http://www.amazon.com/exec/obidos/ASIN/1580530613/o/qid=975621951/sr=8-2/
> ref=aps_sr_b_1_4/107-7655018-3322121>
>
> MULTLIN $259
> <http://www.amazon.com/exec/obidos/ASIN/0890068763/qid%3D975622219/107-765
> 5018-3322121>
>
> <http://www.amazon.com/exec/obidos/ASIN/0890068763/qid%3D975622219/107-765
> 5018-3322121>
> <http://www.amazon.com/exec/obidos/ASIN/0890068763/qid%3D975622219/107-765
> 5018-3322121>
>
> scott
>
>
>
> Larry Miller wrote:
>
>
>
> ***WHERE*** do you get Linpar, please? The only references I find
> are to a 1992 book/disk package with a DOS version.
>
> I would really appreciate a pointer to where I can get it from
> someone!
>
> Thanks,
>
> Larry Miller
>
> -----Original Message-----
> From: MikonCons@aol.com [SMTP:MikonCons@aol.com]
> Sent: Thursday, November 30, 2000 10:47 AM
> To: si-list@silab.eng.sun.com
> Subject: Re: [SI-LIST] : Linpar 2-D field solver experiences?
>
> In a message dated 11/21/00 9:58:22 PM Pacific Standard
> Time,
> chengson@juniper.net writes:
>
>
>
>
> Has anybody used the Linpar CAD 2-D field solver?
> I've used ansoft, CALIF, Greenfield, Pacific Numerix,
> and have recently come across Linpar.
>
> Linpar seems to be a very easy to use CAD tool, and
> seems very cost effective (sub $500) for a general
> purpose 2-D field solving tool for simulating impedance
> and crosstalk.
>
>
>
>
>
> Dave:
>
> I have not tried the latest Windows version of LINPAR, but I
> have used MSDOS
> versions of both LINPAR and its companion program LINRES for almost
> a decade
> with very positive results/success. I also have used Agilent's
> APPCAD,
> Polar's CITS25, and UltraCAD's T-Line Calculator. Relative to the
> real world
> (i.e., documented by measurement on known physical layups), LINPAR
> has been
> one of the best.
>
> A MAJOR ADVANTAGE of LINPAR over the other free (or low
> cost) programs is
> that it can address multiple traces, including different sizes,
> simultaneously. Because of the coupling of adjacent traces in
> today's densely
> routed boards, the individual trace loading and crosstalk is
> important to all
> SI engineers. Most pay an arm and a leg for CAD programs that
> (rightly)
> address this issue, but their accuracy (as you might have noticed)
> has often
> been questioned in this SI forum.
>
> The (purely text) output is in the form of L-R-C-G matrices,
> as well as Er
> (effective), propagation speed, and individual trace impedances. For
>
> crosstalk and waveform simulations, these matrices must then be
> imported into
> the LINRES program, sources and loads defined and saved into
> additional
> files, and then run. The simulation plots from LINRES are very
> basic, but I
> have compared the results with HSPICE W-element simulations and
> FOUND
> NEGLIGIBLE DIFFERENCE (except in the HORRENDOUS difference in
> price).
>
> However, LINPAR/LINRES (MSDOS) has definite limitations. The
> ease of use is
> cumbersome to execute several combinations of trace widths, trace
> spaces,
> dielectric thicknesses, Er values, etceteras. Because of the
> original MSDOS
> program size limitations (from a decade ago), more complex
> structures are
> limited in size. And, with today's thin dielectrics, stripline trace
>
> thickness and shape has an impact on the impedances and crosstalk
> that is not
> accounted for (infinitely thin traces are the default for
> stripline), unless
> you draw a full 2D picture of the configuration. This latter
> approach is
> cumbersome and time consuming, but can be done. The infinitely thin
> traces
> yield higher (~5%) Zo predictions than reality unless the dielectric
>
> thickness is >5 x trace thickness. However, microstrip trace
> thicknesses ARE
> accounted for.
>
> NOTE: The newer Windows version of LINPAR may have corrected
> all of the above
> negatives/limitations. Further comments from any who have tried it
> are kindly
> solicited.
>
> Dave, if you have received other responses NOT sent to the
> SI List, could you
> summarize them and post them?
>
> Mike
> Michael L. Conn
> Owner/Principal Consultant
> Mikon Consulting
> (408)727-5697
>
> *** Serving Your Needs with Technical Excellence ***
>
> --
> Scott McMorrow
> Principal Engineer
> SiQual, Signal Quality Engineering
> 18735 SW Boones Ferry Road
> Tualatin, OR 97062-3090
> (503) 885-1231
> <http://www.siqual.com>
>

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