#### saad

##### Advanced Member level 4

I am using pMOS input differential pair in a single stage opamp. I want to increase the transconductance (gm) of the input pair. I increase aspect ratio (W/L) to decrease Vdsat; hence expecting gm to increase.

On the other hand; Vds drop is decreased whereas Vdsat and gm remain almost unaffected (simulation results are given below). How can I keep Vds constant or increase gm instead? Can anyone help?

W/L = 60

Name: m1

Model: cmosp

Id: -9.90e-05

Vgs: -9.39e-01

Vds: -5.28e-02

Vbs: 0.00e+00

Vth: -5.07e-01

Vdsat: -3.59e-01

Gm: 2.15e-04

Gds: 1.73e-03

Gmb 8.41e-05

W/L=120

Name: m1

Model: cmosp

Id: -9.95e-05

Vgs: -9.14e-01

Vds: -2.70e-02

Vbs: 0.00e+00

Vth: -5.08e-01

Vdsat: -3.44e-01

Gm: 2.25e-04

Gds: 3.54e-03

Regards,

Saad