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Design >> Analog Design >> About Model Statement
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Message started by qiushidaren on Jan 10^th, 2007, 2:02am

Title: About Model Statement
Post by qiushidaren on Jan 10^th, 2007, 2:02am

Hi all,

I am just a newbie in analog IC design, so I am not so familiar with some issues regarding models, could you help me?

Here is my question. What do the statements listed below mean?
section pstat
section pt
section ps
section pf
section psf
section pfs

Regards,
Terry

Title: Re: About Statement
Post by ACWWong on Jan 10^th, 2007, 2:22am

The statements are defining sections within the model file. Each section defines a particular model set for simulating a particular process corner. You PDK will tell you what each section is for, or you can simply inspect the model file itself to deduce (often the model file has useful comments).
Anyway as i don't know your process I would GUESS the following:
pstat: process statisical (for use with monte-carlo)
pt: process typical
ps: process slow (all devices slow)
pf: process fast (all devices fast)
psf: process slow nmos, fast pmos
pfs: process fast nmos, slow pmos

But please confirm by inspecting your PDK or model file directly.

cheers
aw

Title: Re: About Model Statement
Post by qiushidaren on Jan 10^th, 2007, 6:37pm

Hi Aw,

Thanks for your helpful reply, but there are still symmetric statements like:
section nstat
section nt
section ns
section nf
section nsf
section nfs
Maybe the p here doesn’t stand for process?

Regards,
Terry

Title: Re: About Model Statement
Post by ywguo on Jan 11^th, 2007, 5:26pm

Hi, Terry,

First you'd better read the relative documents. If you have not answers yet, you should ask the foundry or who give you the model for the exact meaning of those acronyms.

Yawei

Title: Re: About Model Statement
Post by Croaker on Jan 12^th, 2007, 8:52am

I'd say n is for NMOS and p is for PMOS. I'm not clear on how you could have nsf where the model is slow and fast...

qiushidaren wrote on Jan 10^th, 2007, 6:37pm:

Title: Re: About Model Statement
Post by ACWWong on Jan 13^th, 2007, 4:08am

hi Terry,
as you can see, we can all guess at what it might mean, you can only confirm by either consulting your foundry or PDK (process design kit). In in the event they don't tell you the answer you can only then make an informed guess by inspecting the model files themselves and looking at them (as they are textual, it should be possible to fathom what each section is doing with respect to each other).
anyway, as i find it rather fun, i would guess that n is for nmos, p is for pmos and that there are two types of each FET (perhaps thin and thick oxide... which way round sf or fs... now that's real 50:50... but i'd say thin oxide first ;) . Of course i could be completely wrong)
cheers
aw