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From: howard@cpocd2.UUCP
Newsgroups: comp.lsi
Subject: Re: Internal time step error in SPICE2G6 ?
Message-ID: <571@cpocd2.UUCP>
Date: Fri, 10-Apr-87 01:39:07 EST
Article-I.D.: cpocd2.571
Posted: Fri Apr 10 01:39:07 1987
Date-Received: Sat, 11-Apr-87 21:36:43 EST
References: <8704090953.a008691@Huey.UDEL.EDU>
Reply-To: howard@cpocd2.UUCP (Howard A. Landman)
Distribution: world
Organization: Intel Corp. ASIC Services Organization, Chandler AZ
Lines: 25

In article <8704090953.a008691@Huey.UDEL.EDU> Foster@UDEL.EDU writes:
>	I have been attempting to run some simulations of some dynamic
>	CMOS circuits using SPICE2G6 and encountered some problems with
>	the numerical integration time step. The circuits are very simple
>
>	The error I get in the output file is "INTERNAL TIME STEP TO SMALL".

(1) SPICE doesn't always converge.  It's a bug.  Some people say in the models,
    something about a discontinuous second derivative or something.
(2) UC Berkeley ain't gonna fix it.  They're busy working on fancier things,
    like waveform relaxation.  They are no longer in the SPICE support business.
    They tried, really they did, but it just got too painful.
(3) There are several commercial companies (Meta-software with HSPICE, Shiva
    with Power-SPICE, ...) who would be happy to charge you around $50K for
    a slightly enhanced version of SPICE which they claim will always converge.

Your choices are A. live with it, or B. fork out the money and pray,
or C. get the source to SPICE (easy) and fix it yourself (ha, ha),
or D. switch to a different simulator.  Isn't life wonderful?
-- 
Copyright (c) 1987 by Howard A. Landman.  You may copy this material for any
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