problem with "PMOS in triode" on multisim

[evilheart]

hi guys ,
i want to simulate one stage of Voltage controlled oscillator on multisim ,
i am using a differential stage with PMOS working in the triode as loads.

it seems i have a problem using the PMOS , it doesn't gives the ON-resistance i want , and doesn't follow the equation

R(on) = 1 / 2K (VGS - VTH)

i tried to calculate K using a test circuit and the above equation , but it seems to be changing with different VGS !!!!!
is there something i missed or the problem is with multisim itself???

 

[john blue]

Apparently the Mosfet you have chosen is generic and doesnt have manufacturer. Try picking on those with manufacturer