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How to characterize Transistors for gm/Id based design.

Last post Wed, Mar 19 2014 7:11 AM by Abhishek D. 1 replies.
 Started by Meraj 28 Sep 2013 02:34 AM. Topic has 1 replies and 1112 views
• Sat, Sep 28 2013 2:34 AM

• Meraj
• Joined on Sat, Sep 28 2013
• Posts 1
• Points 20
How to characterize Transistors for gm/Id based design.
 Hi,Q1.  Can someone give the circuit for characterizing Transistors for gm/Id based design, as I found different circuits in differrent        websites. Also what size of W should be taken when generating plots as I am using 180nm Technology.   Q2.  I am able to plot  fT vs gm/Id for single length after going to axis and changing "plot vs". But when I try to plot fT vs gm/Id for various L by using parametric analysis I am unable to get the fT vs gm/Id for various lengths. Is it possible or skill code is required.Thanks in advance.
• Post Points: 20
• Wed, Mar 19 2014 7:11 AM

• Abhishek D
• Joined on Fri, Oct 26 2012
• Bangalore, Karnataka
• Posts 14
• Points 220
Re: How to characterize Transistors for gm/Id based design.
 Ans1) - you can use a common source stage to use. To fix Vds , you should use opamp in negative feedback and one of the end of the opamp should ne the vds. General thumb rules for plotting :-1) W >> Wmin ( to start with 10 times say 10um for 5uA of dc current )2) L= Lmin ( can start with that = 180nm )  Ans2) you must be able to plot with the method you described. You must have missed something.Please share your  experience , I am also very new to this method. Best RegardsAbhishek
• Post Points: 5
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 Started by Meraj at 28 Sep 2013 02:34 AM. Topic has 1 replies.