From: Ray Anderson (Raymond.Anderson@eng.sun.com)
Date: Thu Nov 30 2000 - 14:08:05 PST
You can get a free limited capability demo version of
Linpar (and about 15 other Artech s/w titles) at the
Not sure what the limitations are, but it is free. Caveat Emptor!
> From: "Larry Miller" <firstname.lastname@example.org>
> To: MikonCons@aol.com, email@example.com
> Subject: RE: [SI-LIST] : Linpar 2-D field solver experiences?
> Date: Thu, 30 Nov 2000 12:03:57 -0800
> MIME-Version: 1.0
> ***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!
> Larry Miller
> > -----Original Message-----
> > From: MikonCons@aol.com [SMTP:MikonCons@aol.com]
> > Sent: Thursday, November 30, 2000 10:47 AM
> > To: firstname.lastname@example.org
> > Subject: Re: [SI-LIST] : Linpar 2-D field solver experiences?
> > In a message dated 11/21/00 9:58:22 PM Pacific Standard Time,
> > email@example.com 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 ***
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