Re: gEDA-user: SPICE/gEDA updated. . . . .

[mcmahill@mtl.mit.edu]

On Tue, 25 Mar 2003, Stuart Brorson wrote:

> [ . . . . . . .   Snip!!! . . . . . ]
> > > Yeah, thanks.  Now some questions:
> > > 
> > > 1.  Will the parameters of the calculations apply to *all* MOSFETs?
> > > Or to just those whose model-name is "nmos"?    The point here is that
> > > I need to know what attribute to key off of -- the (DEVICE or REFDES)
> > > or the MODEL-NAME.
> > 
> > The parameters can be expected to vary based on the device.  For example,
> > some MOS processes offer options like a low threshold voltage device or a
> > thicker oxide device to support a higher voltage I/O.  The design rules
> > would be different for these devices.
> 
> So that means that each device of a particular geometry must have an
> individual MODEL-NAME & incorporation of technology file information
> would key off of the MODEL-NAME.

this line should probably say 'each device of a particular family'.  Ie,
all regular threshold nmos devices would call the same model (perhaps
'nmos') all low threshold devices would call that model (perhaps
'nmos_native'), etc.

> > > 2.  Are the formulas used the same for  all MOSFETs?  Or does they vary
> > > from model to model?  (Note that I don't mean the coefficients, but
> > > rather the actual form of the formulae.)
> > > 
> [. . . . . . . . .]
> > 
> > I _think_ the formulas should be constant for different processes but with
> > different parameters.  However, I can't claim to have enough experience in
> > delving into that level of detail on the cad system for enough different
> > processes to be sure.
> 
> Do you have any friends who are device physicists who could answer
> this question?  I can ask around, but it may take a while . . . .

I can ask a few people.

-Dan