Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

[SOLVED] transconductance (u*Cox) parameter dependency to technology

Status
Not open for further replies.
A

ahmadagha23

Guest
hi
Do you know the relationship between transconductance (u*Cox) parameter and technology?
In other words how does change that parameter for a mosfet in .25 micron to 0.18micron?
Regards
 

Re: transconductance (u*Cox) parameter dependency to technol

Hi
Please read this topic , people in this forum discuss a lot about uCox. Thanks
 

Re: transconductance (u*Cox) parameter dependency to technol

ahmadagha23 said:
... relationship between transconductance (u*Cox) parameter and technology?
In other words how does change that parameter for a mosfet in .25 micron to 0.18micron?
Click to expand...
Below pls. find a table with those parameters for 3 different processes from D. Binkley's book "Tradeoffs and Optimization in Analog CMOS Design".
For 0.25µm tech., you can interpolate.
 

Hi Erik,
The document you attached does not include the division factor of 2 in the computation of Kn or Kp. Why would that be or is it always that case. If so, the other edaboard link mentioned in this post clearly shows that we have to include the factor 2 in the computation of Kn or Kp.

Also one more trivial question. Why is it called as Transconductance parameter. If my interpretation of this name meaning is right, then the computation of Kp or Kn doesnt involve the factor 2 (gm = (2*Id)/Vov).But still I miss thhe squared (Vov)^2 in the interpretation of this formula though

Thanks for helping

Falcon
 

the_falcon said:
The document you attached does not include the division factor of 2 in the computation of Kn or Kp. Why would that be or is it always that case. If so, the other edaboard link mentioned in this post clearly shows that we have to include the factor 2 in the computation of Kn or Kp.
Click to expand...
Unfortunately the use of this division factor of 2 is handled differently in various books, depending on if it's already included in the transconductance factor (e.g. k'=k/2 or C'ox=COX/2) or not.

the_falcon said:
Why is it called as Transconductance parameter. If my interpretation of this name meaning is right, then the computation of Kp or Kn doesnt involve the factor 2 (gm = (2*Id)/Vov). But still I miss the squared (Vov)^2 in the interpretation of this formula though
Click to expand...
Do not mix up the Transconductance parameter k'=µ0*C'ox [A/V2] with the transconductance gm = (2*Id)/Vov given in units of [A/V] !
 
thanks for the posting erik and also informing about the Kp parameter
Regarding the transconductance parameter, then I am really curious to know how it got named in that way if it has nothing to do with the transconductance(gm).

thanks
Falcon
 

Given Id=K/2*W/L*Vov^2
gm=K*W/L*Vov

K is essentially the transconductance per W/L per volt of overdrive.
It's just a normalisation procedure.
And that explains why it should not include the "divide by 2".

Added : This assumes that the MOS follows the simplistic square law.
For high density processes, deviations from the square law are bound to occur.
 
thanks checkmate
that was a brilliant explanation in my opinion.

besides being happy for it, I am still curious to know as how erik got the right answers as in datasheet for both Kp and Kn values.

falcon
 

the_falcon said:
... how it got named in that way if it has nothing to do with the transconductance(gm).
Click to expand...
There's a convenient relation between the transconductance parameter k' and the transconductance gm :
gm = k'/n * W/L * Vov , s. e.g. David M. Binkley "Tradeoffs and Optimization in Analog CMOS Design" equ. (2.12), where n is the substrate factor.
 
Thanks Erik for mentioning about the transconductance parameter.
But could you please tell me as how you managed to get the right answer by having the factor '2' in your computation of Kp and Kn in the mentioned post happened before

falcon
 

the_falcon said:
... could you please tell me as how you managed to get the right answer by having the factor '2' in your computation of Kp and Kn in the mentioned post happened before
Click to expand...
I think it's comprehensibly explained in the "mentioned post happened before". Don't forget:
erikl said:
Unfortunately the use of this division factor of 2 is handled differently in various books, depending on if it's already included in the transconductance factor (e.g. k'=k/2 or C'ox=COX/2) or not.
Click to expand...
 

Thanks Erik. I will refer to the mentioned book for more details.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top