Help! Anyone who are familiar with spice3 source code?

My boss asked me to modify spice MOSFET model equation. I have studied
spice3f5 source code a few days but I can't understand. There are too many
files. I don't know even the basic structure of source code. I have only one
month time. Is there anyone who can help me? Thanks in advance!

 

Why?

Which model, 1, 2, 3 bsim3?

Maybe. What do you want to do. Some things are easy, some things you
shouldn't mess with until you've figured out the code in more detail.
Some things you should never mess with

Kevin Aylward

http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.

 

Ditto on that. Messing with the MOS equations on Spice 2 or 3 can
result in major accuracy and convergence problems that you may never
solve. I've been using Spice and doing device model extraction for 20
years and you couldn't pay me to jump into that code base to do that.
And that's with 20 years of C (and C++, Java, etc.) experience to
boot. I'd sooner start a new simulator from scratch.

Generally for the average Spice user only want to mess with device
models when you are using a Spice or Spice-like tool that was
specifically designed for user modifications. The issue is that in
Spice there are two areas of iterative numeric computation (non-linear
DC analysis and then transient analysis) which can be seriously messed
up with bad or malformed model equations. "Bad" can mean flawed
companion model, 1st or 2nd derivative discontinuities, etc. Consider:
why would everyone mess SUBCKTs or analog behavioral commands if you
could easily write some C and drop it in? It's because you usually
can't.

http://www.ecircuitcenter.com/Circuits/ABM1/ABM1.htm

It should also be noted that most/all of the MOS models were
originally PhD theses. Any one of the current models available will
probably be better than what you come up with. Just food for thought.

Despite that "fear-of-god" speech, here's a place to start. This is a
nice online exposition of how Spice works:

http://www.ecircuitcenter.com/SPICEtopics.htm
http://www.ecircuitcenter.com/SpiceTopics/Overview/Overview.htm


MM

 

I need to add BSIMSOI3. I tried to add BSIM4 as a test according to
instruction I got from berkeley website. But it can't work for bsim4. When I
run a circuit example it always allert undefined parameter.

I have studied spice3f5 souce code a few days. But I find I am wasting time.
Can you give me a detailed description about spice3 source code?

 

Thanks. Even if I will fail I want to have a try. I found the website you
listed. There are lots of useful information. But I can't find anything
about the organization of spice source code.

I am doing parameter extraction too. Can you tell me which tools have you
used to extract model parameter? I have extract model parameter for SOI PD
MOSFET. But there are two problem:
1. The simulation curve can't simulate kink effect.
2. The simulation curve is quite different with measure curve when a
substrate voltage is added.

My tutor said maybe the soi model is not mature. He asded me to modify the
model equation and extract parameters. He doesn't realize the hardness of
the work. I need to find a more accurate model equation that can simulate
kink effect. Then I need to modify model equation in spice. Finally I need
to extract model parameter.

These days I feel I am wasting time. I can't get any progress.

 

berkeley

 

hi
I have sent you my spice3. Have you had a look?