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# How to find LAMBDA of a MOSFET

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#### satyakumar

##### Full Member level 3
mosfet lambda

Hi all,
Can any body help me in finding LAMBDA of MOSFET from W,L,Id,(Vgs-Vt)
Thanks to all
Regards
satyakumar

#### pankajdudulwar

##### Full Member level 2
how to find lambda

Hi!
Lamda is the process parameter and it is not any design parameter that u have mentioned. For process parameter I feel u have to give look to the semiconductor processes and the BSIM manual were it will be mentioned how lamda is calulated.

##### Full Member level 5
lambda mosfet

In BSIM no straight formula for lambda exist because it depnds on many different parameters. but for your hand calculations you can simulate a simple ckt (as CS) and then from the output paramters of spice make an approximation about lambda: Id=K/2* (Vgs-Vt)^2*(1+lambda*Vds)

#### ryusgnal

mosfet lamda

Lamda is not fix value for the transistor. It is varies for different biasing and different model of transistor. you can find it by drawing the Id-Vds curve and find the gradient At the specific biasing you want at the curve. The gradient is lamda value. that is what i know.

#### cinch

##### Member level 2
how to find lamda

λ = 1 / (2*Rout*I)
Rout = gain / gm

#### pmr9

##### Junior Member level 2
Î» lambdaã€€hspice

Lambda varies with process ,device parameters and more. simualte simple fet Id ,Vds char and extend the I line to - axis of Vds ,the point it cuts gives u 1/Lamda.
Or if u have Gds of ur fet ,then Lamda=Gds/Id
Note that its different for diff. values of Id also

#### bsshwetha

##### Newbie level 3
how to find lambda?

As it is known, λ is fixed for a give value of W/L, Vgs, Vds. Thus, for a given transistor, fix all these for the MOS to work in the saturation region and run a DC Operating Point simulation.

Look into the values of rds of the MOS and the Ids thro' it.
Calculate λ using the following relation:

λ = 1/(rds*Ids)

Hope this helps!!!

#### kumar123

##### Member level 3
parametro transistor mos lambda

satyakumar said:
Hi all,
Can any body help me in finding LAMBDA of MOSFET from W,L,Id,(Vgs-Vt)
Thanks to all
Regards
satyakumar

attached some doc on the procedure to extract lambda

Points: 2

### Akami000

Points: 2

Points: 2

#### st_james

##### Newbie level 4
thanks a lot........

#### st_james

##### Newbie level 4
thanks again

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