Why 'gate width' is important?

[CQCQ]

Hi!Why 'gate width' is important in amplifier or mosfet? large gate width or small gate width which is good and why?

THS!
-CQCQ

 

[deh_fuhrer]

More is the gate width more is the transconductance of the device....

 

[khouly]

as the gate width increase that mean more current can pass through ur device , and also the transcondacutanc
this means higher gain

khouly

 

[roadbuster]

The drain current of an n-type MOSFET in saturation is given by:

\[ I_{DS} \hspace{4mm} = \hspace{4mm} \frac{1}{2} \mu_{n} C_{ox} \frac{W}{L} \left[ 2(V_{gs} - V_{t})V_{ds} - V_{ds}^2 \right] \]

The W term refers to the gate width of the transistor. As you can see, increasing the gate width will increase the drain current of the transistor. The benefits of a higher drain current should be obvious.

The transconductance of the n-type MOSFET in saturation is given by:

\[ g_{m} \hspace{4mm} = \hspace{4mm} \frac{dI_{d}}{dV_{gs}} |_{V_{ds} = const} \hspace{4mm} = \hspace{4mm} \mu_{n} C_{ox} \frac{W}{L} (V_{gs} - V_{t}) \]

Once again, there is a linear relationship between transconductance and transistor gate width. A higher transconductance means that you can build an amplifier with a higher gain.