Re: [Fwd: comments on paramsets]


Subject: Re: [Fwd: comments on paramsets]
From: Geoffrey.Coram (Geoffrey.Coram@analog.com)
Date: Fri Nov 14 2003 - 12:47:47 PST


Jim -
In a typical Spice netlist, one does not instantiate "bsim3"
and correspondingly in Verilog-A, I wouldn't expect to give
the module name (bsim3) but rather the name of the paramset.

Perhaps you are concerned that in a Spice netlist, the
instance line of a mos device starts with "M" (and the
model name comes later). You have a valid point that
the "instance name" of a Verilog-A device may or may not
fit the Spice tradition (M for mos, Q for bjt, ...); if
the simulator folks require an instance name starting with
X for all Verilog-A devices, then it becomes difficult to
find all the mosfets in a netlist. If the simulator folks
allow M1 to be a Verilog-A-defined mosfet, then the
instance line will look exactly the same. (In fact, I think
Tiburon's setup works this way.)

From an instance line
   M1 d g s b n180nm l=0.18u w=1u
you won't be able to tell whether n180nm is defined as a
traditional Spice .model card or as a paramset.

-Geoffrey

"J.A. Barby" wrote:
>
> Geoffrey,
>
> With point 1, the paramset proposal on the www site says
> To use a paramset, one simply uses the name of the paramset in lieu of
> the name of a module when instantiating an instance of the underlying
> module.
> This requires a mindset change on the user's part and drops the
> readability of the netlist. Instead of instantiating a mosfet, they
> are instantiating a paramset (parameterized mosfet module).

-- 
Geoffrey J. Coram, Ph.D.    Senior CAD Engineer     
Analog Devices, Inc.        Geoffrey.Coram@analog.com 
804 Woburn St., MS-422,     Tel (781) 937-1924
Wilmington, MA 01887        Fax (781) 937-1014



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