Re: [Series MOSFET] keyword

Vds, the drain-to-source voltage, is indeed the voltage between the
the 2 pins of a [Series MOSFET] model. IBIS leaves the gate up to the
simulator - there is no third pin defined for it. In some simulators
(at least SPECCTRAQuest) you can wire the gate to any voltage source
you want.

I like to test series switch models using a gate voltage source that
turns on and off at a frequency that is different from the clock
frequency of the signal passing through the switch. This way you can
study how far in advance the signal must stop changing before it is
safe to switch. You can also inject noise into the gate voltage to
see how much of it appears on the signal.

Mike LaBonte
Cadence Design Systems

Kim Helliwell wrote:
>
> I'm trying to understand how series models work, and the explanation
> in the 3.2 spec for the [Series MOSFET] keyword has me confused.
>
> The spec says that Vtable is Vgs = Vcc-Vs. What I'm unclear on is
> the where the subparameter Vds comes in. From the model, it appears
> to be the voltage difference between the pins that are in series.
>
> I think my problem is we are specifying two pins connected by the
> series model, so how does the third pin (the gate) get hooked up
> and modeled by a simulator?
>
>
> --
> Kim Helliwell
> Senior CAE Engineer
> Acuson Corporation
> Phone: 650 694 5030 FAX: 650 943 7260
Received on Fri Aug 11 06:11:24 2000