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.

Is it feasible to use Vgs somewhat less than Vth ?

Status
Not open for further replies.

jdp721

Member level 2
Member level 2
Joined
Jun 29, 2009
Messages
45
Helped
4
Reputation
8
Reaction score
3
Trophy points
1,288
Activity points
1,621
Is it feasible to use Vgs somewhat < Vth ?

Hi,

In an opamp, we can set the input-pair MOSFETs to be in Sub-threshold region of operation.

To what extent can we put them in sub-threshold?...like, can we use (Vgs - Vth) negative?
As I searched in forum posts, people say they use (Vgs - Vth) ~ 100-200mV which makes the MOSFET near subthreshold..but is it feasible to use a Vgs somewhat < Vth ?
If yes, how much negative?

I am using UMC 180nm process...but any general info is also welcome.

Thanks..
 

Re: Is it feasible to use Vgs somewhat < Vth ?

Yes, Vgs can be less than Vth.

Making them in the sub-threshold region has higher gm/id, more power efficiency and higher gm, which is good for noise minimizing and matching.

If you want very high bandwidth, you need to make it in the saturation region, making Vgs > Vth.
 
  • Like
Reactions: jdp721

    jdp721

    Points: 2
    Helpful Answer Positive Rating
Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top