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ccw27
Joined: 13 Oct 2004
Posts: 292
Helped: 8
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 07 Jan 2005 7:57 MOS model for design |
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Hi,
Given a new process, what do Analog IC designer do before they start using the process for actual design? I am talking about what sort of simulation is typically done beforehand so that a good model is obtained in order to get a good approximation when sizing the transistors? Is Id/W vs. Vgs-Vt plot for different lengths a good model or the good old square law still used?
Thanks
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chinito
Joined: 05 Jul 2004
Posts: 133
Helped: 4
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| 07 Jan 2005 19:44 Re: MOS model for design |
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| for design, square law is used to get back-of-the-envelope numbers. Then you get process parameters Kn, Kp, gm, ft, vtn, vtp etc from simulation.
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ccw27
Joined: 13 Oct 2004
Posts: 292
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| 08 Jan 2005 3:17 Re: MOS model for design |
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Could anyone provide a reference or summary on how I can go about extracting each transitor parameter in simulation?
Thanks
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qutang
Joined: 25 Oct 2004
Posts: 315
Helped: 6
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| 08 Jan 2005 10:38 MOS model for design |
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| SEE THE HELP OF CADENCE.
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rongli
Joined: 13 Dec 2004
Posts: 35
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| 08 Jan 2005 13:18 MOS model for design |
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berkeley's web maybe have it /
Warning. Almost all your posts are few words long and useless. Stop hunting points. Give links, give real help, not answers like "try on google".
/pisoiu
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yilmazerc
Joined: 11 Jan 2005
Posts: 10
Helped: 1
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| 11 Jan 2005 23:16 Re: MOS model for design |
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Maybe you can find a K to use in Id=K(Vgs-Vt)^m
m is approximately 1 for short channel transistors
To calculate lambda Id vs. Vds curve can be used
slope of the curve=(lambda*Id)
but all these are just an approximation for hand analysis you must do many iterations to find the required value.
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nickooeda
Joined: 15 Sep 2004
Posts: 44
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| 13 Jan 2005 6:05 MOS model for design |
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| the solution is in the appendix of in ALLEN's book [cmos analog intergrated circuit design]
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yyliang
Joined: 26 Aug 2004
Posts: 43
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| 13 Jan 2005 9:41 Re: MOS model for design |
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Bsim level 3 model
you can find it in many places
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thcm
Joined: 13 Jun 2004
Posts: 55
Helped: 3
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| 13 Jan 2005 9:45 MOS model for design |
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First, you should check model accuracy by comparing
simulation results with measuring data from foudry;then you can easily get level 1 parameters,from id-vd,or gm-id curves .
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SkyHigh
Joined: 13 Jan 2005
Posts: 376
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| 13 Jan 2005 17:54 Re: MOS model for design |
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Dear ccw27,
You can adopt BSIM3 version 2 or MOS Model 9, however both are accurate to HCMOS 11 only.
You can extract suggested parameters from EDA CAD. Many Digital IC Designer do that.
However Analog IC Designer do this in a professional way by actually model the MOS device which is used in the circuit, then simulate the (I-V) transconductance characteristic curves umpteen times until the result is satisfactory. The eventual parameters are extracted and used.
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