How to make a good MOS model for a design?

Status
Not open for further replies.
C

ccw27

Full Member level 5
Joined
Oct 13, 2004
Messages
267
Helped
14
Reputation
28
Reaction score
6
Trophy points
1,298
Activity points
2,558
MOS model for design

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
 

Re: MOS model for design

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.
 

Re: MOS model for design

Could anyone provide a reference or summary on how I can go about extracting each transitor parameter in simulation?

Thanks
 

MOS model for design

SEE THE HELP OF CADENCE.
 

MOS model for design

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
 

Re: MOS model for design

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.
 

MOS model for design

the solution is in the appendix of in ALLEN's book [cmos analog intergrated circuit design]
 

Re: MOS model for design

Bsim level 3 model

you can find it in many places
 

MOS model for design

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 .
 

Re: MOS model for design

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.
 

Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…