Pchannel and Nchannel

Kevin Cameron wrote:

>> [re: -1 as a flag for p-channel]
>
> That's just one way to do it.

The C code for BSIM3 and 4 do it that way, Spice does it with the
BJT and MOS models, Philips does it that way with the MOS11 and
Mextram models, ... In Verilog-A compact models, Mextram is
written that way, as are the ones that Silvaco put on the web.
I challenge you to find a different way that it's done.

> However (if my reading of the proposal is correct) this still means
> you are using a single module (bsim3v3) for both n & p devices which
> will make it difficult to swap to digital primitives i.e. you can't
> drop the bsim3v3 model from the netlist and substitute the appropriate
> pmos/nmos: you would have to add a macromodule with a generate
> statement dependent on the type parameter selecting between the two.

That's implementation-specific. The instances will call for a thing
named "nmos" that would (in my method) usually resolve to a paramset
(referencing the bsim3v3 module). Your method would have it resolve
to a macromodule. But macromodules and paramsets would be in the
same namespace; I don't see why a simulator wouldn't allow you to
insert a digital primitive in the place of either one.

-Geoffrey
Received on Fri May 21 07:24:10 2004