Re: Problems with SPICE models from vendors

From: Helmut Sennewald (helmutsennewald_at_t-online.de)
Date: 03/25/05 

Date: Fri, 25 Mar 2005 11:05:43 +0100

"Robert Baer" <robertbaer@earthlink.net> schrieb im Newsbeitrag
news:1PQ0e.3481$gI5.1145@newsread1.news.pas.earthlink.net...
> The LM324 model from TI works fine,but the one from National
> Semiconductor is junk.
> I tried numerous Analog Devices models for various rail-to-rail opamps,
> and found that almost all i tried gave me the same kind of cryptic square
> root error.
> Those tried: AD8605, AD531, AD541, AD8552, and the AD8571; the only one
> tried that did work was for the AD8614.
> Now i would dearly like to have a set of models that were known to work
> (and more or less correctly), but i need to get a working AD8605 model.
> The sets i have came from the manufacturer created in the latter of
> 1992, and thus are not quite up-to-date.
> However, the model for the AD8605 was downloaded via the web just
> yesterday - implying the problem is not fixed.
>
> Can anyone help?

Hello Robert,
I don't believe that you really can judge the quality of these
models as a beginner with SPICE simulations.
I agree with you that most models have difficulties with convergence.
Many of them are really over complicated and sometimes generated
by stupid programs or "roboters" and not by engineers.

I assume that the listed models will work with some tweaking
of the convergence parameters.

What simulator do you use?
If it's LTspice then send me your files and I will make
you a working example with your AD8605.
I always want to see the schematic, because I know that
people sometimes have errors in their circuit.
One important thing is to have a DC path to ground(0).

Best Regards,
Helmut
Moderator of the LTspice user group

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