Transistor W/L Vs 2W/2L. What is the different.

[wccheng]

Dear all,

Actually, the aspect ratio of the transistor W/L and 2W/2L are the same. As I know, the parasitic capacitor due to the 2W/2L is larger than W/L. Moreover, the 2-nd order effect in 2W/2L is smaller. Except these effects, What is the different between of them?

Thx

wccheng

 

[yeechyan]

The output resistance for a transistor with 2W/2L is higher than the transistor with W/L.

 

[v_naren]

there are noise considerations too!!!
take care of the noise considerations

 

[dcc]

As for the performance of RF circuits, the cut-off frequency (ft) of the deviec with W/L will be larger than that of the devices with 2W/2L. The value of L will determine the operating frequency of the devices.