Feb 21, 2009 #1 K kidmanbasha Member level 1 Joined May 25, 2007 Messages 39 Helped 3 Reputation 6 Reaction score 1 Trophy points 1,288 Activity points 1,587 gm / vgs I am trying to simulate gm/id vs vgs in cadence but I get a strange transition when vgs approaches zero as shown below. How I did the simulation : sweep vgs vs id then using the calculator i get the derivative of id and divide by id to get gm/id
gm / vgs I am trying to simulate gm/id vs vgs in cadence but I get a strange transition when vgs approaches zero as shown below. How I did the simulation : sweep vgs vs id then using the calculator i get the derivative of id and divide by id to get gm/id
Feb 21, 2009 #2 erikl Super Moderator Staff member Joined Sep 9, 2008 Messages 8,108 Helped 2,695 Reputation 5,370 Reaction score 2,305 Trophy points 1,393 Location Germany Activity points 44,123 id vs vgs kidmanbasha said: I am trying to simulate gm/id vs vgs in cadence but I get a strange transition when vgs approaches zero as shown below. Click to expand... It's not weird, it's normal: in sub-threshold (= weak-inversion) you have maximum gm/id , s. e.g. E. Vittoz' weak-inversion paper below (p. 10).
id vs vgs kidmanbasha said: I am trying to simulate gm/id vs vgs in cadence but I get a strange transition when vgs approaches zero as shown below. Click to expand... It's not weird, it's normal: in sub-threshold (= weak-inversion) you have maximum gm/id , s. e.g. E. Vittoz' weak-inversion paper below (p. 10).
Feb 22, 2009 #3 O oermens Advanced Member level 2 Joined Nov 19, 2005 Messages 525 Helped 107 Reputation 220 Reaction score 44 Trophy points 1,308 Location canada Activity points 3,988 vgs vs id you can also use dc analysis and obtain 'gmoverid' parameter.
Feb 22, 2009 #4 K kidmanbasha Member level 1 Joined May 25, 2007 Messages 39 Helped 3 Reputation 6 Reaction score 1 Trophy points 1,288 Activity points 1,587 ids vs vgs cadence erikl...I did as oermens said and the result is as expected without the the sudden peaking at vgs--->0.
ids vs vgs cadence erikl...I did as oermens said and the result is as expected without the the sudden peaking at vgs--->0.
Feb 23, 2009 #5 erikl Super Moderator Staff member Joined Sep 9, 2008 Messages 8,108 Helped 2,695 Reputation 5,370 Reaction score 2,305 Trophy points 1,393 Location Germany Activity points 44,123 id versus vgs kidmanbasha said: erikl...I did as oermens said and the result is as expected without the the sudden peaking at vgs--->0. Click to expand... So the SPICE DC calculations provide a smoother transition from weak <-> strong inversion!?
id versus vgs kidmanbasha said: erikl...I did as oermens said and the result is as expected without the the sudden peaking at vgs--->0. Click to expand... So the SPICE DC calculations provide a smoother transition from weak <-> strong inversion!?
Feb 23, 2009 #6 K kidmanbasha Member level 1 Joined May 25, 2007 Messages 39 Helped 3 Reputation 6 Reaction score 1 Trophy points 1,288 Activity points 1,587 yes. actually the peaking was in the inversion region only cuz the vto of my process (0.13u) is between 0.2 and 0.3
yes. actually the peaking was in the inversion region only cuz the vto of my process (0.13u) is between 0.2 and 0.3