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How to handle Lambda calculation and plotting?

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I dont know how to calculate the output res of the transistor in any configuration, as it involves Lambda(r=1/lamda*Id), is this a process parameter? I dont think so, as the plot changes depending on Vgs, right?? how to calculate or plot it? is there an easy way? or any other way to find output resistance of a transistor?? thnx
 

calculation of lambda calculation

just plot 1/slope of the Id-Vd curve of the transistor that will be the curve of the small signal output resistance. Lambda depends upon the biasing point and also the length of the transistor. You can find Lambda from ro if you want, but once you have ro you won't need Lambda.
 

lamda calculation

Lambda is not a process paramter in BSIM models. Only for wide w and l's lambda makes sense to compute. Using w aad l values in the near of the critical dimension lets vary lambda in a wide range.

However, lambda is taken to compute the rds (rout). So its's better to plot rout directly. Most simulators, so do Cadence, Mentor, ... save a simulation parameter rout or gout. make a paramter plot over different w, l and Ids!
 

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    ASICK

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Re: Lambda calculation

donnot use lamda any more
It not a constant
 

Re: Lambda calculation

So if i need to know the rout of any transistor in a circuit without knowing lambda, what is the bestand easiest way in cadence? what kind of plot will let me know the approm value of Rout, so I can measure my gain and poles without having to know lambda?
 

Lambda calculation

plot ids-vds@vgs curve,then delta(ids)/delta(vgs),the do reciprocal operation.you will get rout curve
 

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