Hi, I am trying to design an OpAmp using sky130 pdk "nfet_01v8 and pfet01v8" but I am facing a problem with the current mirror I think I can not drive the nfet to the saturation and I faced some problem by finding the value of uCox for the transistors

@Abdalkreem Kasasbeh You won’t find uCox as this a bsim4 model.

@Amro Tork I tried to calculate the uCox using the op simulation and through this equation uCox=(gm^2/(2*Id*(W/L))=1.6938e-4, is it right or I need to run DC simulation as you mentioned?

M3 and M4 are in parallel (same source - vdd, same gate - vb2, same drain -vb2). Is that what you want?

@Mitch Bailey no it was bu mistake but even without that mistake I still have the same issue with the current mirror M5, M10 and M6 they should have the same current

are the drain-source voltages across your M5 M10 M6 the same?

@John Kustin no they are not the same, I got the desired result "the current and gm" by making Wm5 =2Wm10 and Wm6=Wm5. what I know is that the mirror transistors have to be the same but here m5 and m10 are not the same

@Abdalkreem Kasasbeh I think it might be a good estimation for further hand analysis.