Re: Paramset Proposal

Kevin -

Spice .model cards are frequently defined within a subckt,
and the simulator is expected to match instances in the
subckt with that .model (with essentially no search) --
not go out to the library file mentioned at top level.
Your suggestion to do some other sort of search is simply
not compatible.

Kevin Cameron wrote:
> > If the corner matches but l&w don't, that's not a match.
> Yes, but if I have a both set and the paramset only requires
> one: that will be a match regardless of a potentially better match.

If you have them "set" then you must have specified them as
instance parameters, and the simulator must find one that
matches both.

If you specify L and W in a spice netlist, and there's a
set of model cards in the library, one of which matches L
(lmin<=L<=lmax) but the foundry forgot to specify wmin,wmax,
that's an error on the part of the foundry. The simulator
shouldn't have to go looking for another model card that
does have wmin,wmax and W is in that range.

> If there are still multiple applicable paramsets the search mechanism
> should start with the most restricted and work down, e.g. if there is

I doubt you can set up a complete set of rules. What if you
specify 3 things, and the simulator finds it can match 2 of 3
for three different models (L&W, L&corner, W&corner) -- does it
now say, gee, the lmin/lmax bounds are tighter, so that's a
"more restrictive" paramset? You'll get down to something
where it will essentially be a coin flip.

> NB: Stuff entered through GUIs tends not to have much ordering to it.

The schematics will be done through GUIs, not the library files.

-Geoffrey
Received on Fri May 14 11:22:45 2004