gm of MOSFET - calculating the lambda of transistor

[dynamac]

gm of MOSFET

Hi
I am new here to EDAboard. I am working on 0.13u technology, I used to previously work on 0.25u technology in College. I am finding it hard to calculate the lambda of transistor(channel length modulation) . Most of my co workers do not calculate at all. I have two questions 1 . Is there any method by which I can calculate lambda or ro . 2. Is theoretical calculation of ro really required to design.

Thank You

 

[antonio_eda]

gm of MOSFET

Read fascinating books of professor Yannis Tsividis about MOSFET modelling. In one of them you can find an easy and accurate model for hand calculations in modern processes.

Calculation of lambda is very important in some applications even with long-channels. In short-channel processes ro is very significant --- it is not infinity anyway.

 

[diemilio]

Re: gm of MOSFET

Check APPENDIX B of Allen & Holberg's - "CMOS Analog Circuit Design"

They have a very straight forward methodology to get all sorts of parameters from either simulation results or measurements.

Hope this helps,

diemilio

 

[edge_tv]

gm of MOSFET

I think it is impossible to model gds (Ro) with one lambda factor. You can plot gds with a simulator and you will see that is hopeless. All calculation (in a short channel process) with the square law equations will be off big time. I use the gm/Id method and I’m very happy with that (see ee240 lecture from Berkeley, you can also watch the video stream on Berkeley webbroadcast webpage).

 

[antonio_eda]

gm of MOSFET

I think, gm/Id method is very good.

 

[hdmi]

Re: gm of MOSFET

hi, edge_TV:

Does gm/Id methodology based on EE240 give you correct gds?
Thanks,