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The issue of using new and old software

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Member level 4
Apr 27, 2002
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new and old

I have a question for all of you.
What is the meaning of having always the latest software and models ?
I saw in many IEEE papers that they use in general SPICE (usualy PSPICE and HSPICE) and level 1 to 4.
They try to present an ideea and not sofisticated simulations results.
Especially for people who want to learn (students) I think they don't need fancy simulators.
The people who works in industry also don't need the latest versions because they work with models and software given by the company and by fab.

Maybe my opinion is not so correct. I expect you to write your opinion.


right tool for the job

Your observation describes me.

My belief is to us an adequate tool for the job.

I still use a SPICE program from about 20 years ago. It is so old that it takes a ASCII text file for an input. I have a microwave simulator that is many years old. I like it because the ASCII text file created from the modules can be conveniently edited. The modern version of this program has user input dialog boxes that take many key strokes to bring up and fill in.

Many newer versions of programs remove useful features and add useless features. I have heard a rumor that the most recent not yet released version of a microwave simulator program has automatic operation of test equipment that few of us own to automatically take measurements most of us do not want.

You are partially right , partially not .

Almost all engineers now use BSIM models , which are levels 49 , 52 depend on your program. Only small fraction of students now use levels like 1 & 3 , that because they use *almost* the hand calculation equations used in books , so they can check their initial design. But come to silicon , you need really sophisticated models for such a job .

If you are talking about SPICE simulators , most enhancements come from added new models or new model upgrades. Also some includes new mathematical algorithms for better convergence & faster operation , which may be VERY critical for some designers.

For me , I don't search for a new version before I see that I can not get what I want from the old one with a reasonable efforts.

Many upgrades indeed are done for bug fixing in GUI & some other issues that will not affect your design if you are smart enough , & some may only exist to renew the old strings that were used to generate a license for elder version !!!

The fab only provides you with a model card ( model parameters) ( or a whole design kit) that don't contain a software of course. But they provide you a kit suitable for YOUR program (HSPICE , ELDO , Cadence...etc) that will generate a simulation that is very close to silicon in their fab. If you want to design an SOI chip & you don't have program contains an SOI model , you must find one .

Hope that helps

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