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Subject: Re: [geda-user] git mirror of gedasymbols.org
From: John Doty <jpd AT noqsi DOT com>
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Date: Tue, 20 Nov 2012 10:41:43 -0700
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On Nov 20, 2012, at 9:10 AM, Evan Foss wrote:

>> I firmly believe, that it is possible to assemble generic models that can
>> be tuned according to data sheet parameters. These may not be the most
>> efficient, or the most realistic models. But they can provide a starting
>> point and possibly a seed for better models.
> 
> This premiss is not going to fly. I have models from manufactures for
> some analog parts where they bothered to build very large structures
> in spice one transistor/diode at a time. There is just no way some one
> bothering to model a circuit would want to turn that down in favor of
> a generic model. While I can appreciate the importance of building a
> totally open source library I just can not see investing this level of
> time.

Exactly.

> 
>>> I'm also considering the
>>> possibility of automating the fetch of a model from a URL.
>> 
>> IMHO, it would be better to provide idealized open source models that
>> can be modified and improved over time. Download of closed source models
>> is just a band-aid.
> 
> To help new users understand spice better I could see building a few
> heavy symbols of ideal parts into the standard gEDA suite library so
> that they can see how that works.

And, as Kai-Martin should remember, for opamps such models exist at http://www.gedasymbols.org/user/john_doty/models/opamp/index.html, but I have no intention of taking this any farther for the reasons you so eloquently gave above.

The macromodels at http://www.gedasymbols.org/user/john_doty/symbols/openIP/ are intended for ASIC design, but I sometimes find myself using them for parts in other mixed-signal design simulations when models of commercial parts are unavailable. The good news is that Professor Ikeda, who provided the models, also has published extensive documentation. The bad news for most reading this is that the documentation is in Japanese. If I find myself with *a lot* of time on my hands, I may attempt to translate it.

John Doty              Noqsi Aerospace, Ltd.
http://www.noqsi.com/
jpd AT noqsi DOT com