Why we use GMmax to define the VT.

[xuws]

gmmax

There are two common methods to measure VT.
1:define Id=+-0.1uA
2:Vth Measure method:
> Step1:Vds=0.1 Vs=Vb=0 and sweep Vg
> Step2lot Ids µ Vgs and Gm µ Vgs curves Step3:find Gm(max),plot slop
> of this point on Ids Vgs From Linear function set Id=0 then
> Vth=Vgs-0.5Vds

the second method?
why GM first increases then decrease?
why we get VT at Max Gm point?
Is there any paper or patent to explain the theory?

Wait for your kingdly help,thanks!

 

[erikl]

gmmax method

... why GM first increases then decrease?

Is there any paper or patent to explain the theory?

gm/Id is maximum in weak inversion, s. the papers below:

 

[equantum]

vt by gmmax method

thanks very much...