--- In LTspice@..., Message 141, Panama Mike
<panamatex@y...> wrote:
< snip >
BTW, I'm thinking of introducing opamp models that
use a different modeling methodology, similar to
that used for LTspice's SMPS products. The result
would be computationally extremely lightweight and
robust models that model noise too(these PSpice-
style opamp models almost never get the noise
modeled). However, the opamps models would not
run in other SPICE simulators and non-LT opamp
models wouldn't be available. Would you folks be
interested in something like that?
--Mike
Mike, this sounds like something I'd like to dissuade you from.
Part of the strength of the SPICE methodology is that the models are
transmitted as "open source", simple text files. The most significant
advantage is that we Mere Mortals can easily extend, improve, correct,
or modify models as needed.
The parent thread for this posting is a good example. Because almost
everything about the model was in plain view, several minds were
independently analyzing the problem and solving it. I cannot imagine
the problem being resolved nearly as quickly if the model's topology
and parameter values had been locked-up in a proprietary format
readable only by a few people.
The SPICE methodology permits individuals to customize models as
needed. If, for instance, noise is a critical performance
characteristic the necessary elements can be readily included to model
it. Otherwise they may be omitted. Similarly, a small-signal stage
where output limiting is not a concern can get by with a simplified
output circuit in the model.
Along the same line it is relatively easy to adjust model parameters
to fit particular situations. The model can be customized to reflect
the device's behavior at, say, a temperature extreme. Or an engineer
can investigate the implications of using a device whose performance
parameters (like offset voltage or slew rate) are near the data sheet
limits. Likewise the need for parts specially selected for certain
characteristics (such as low offset current) can be evaluated.
Finally the current SPICE modeling methodology allows engineers to
quickly create workable models for new or alternative components.
I hope that whatever modeling methodology you choose will retain these
features.
Dale
