the propagation delay of the pseudo nmos inverter

[salma shabayek]

pseudo nmos inverters

Dear all,

Im supposed to calculate the propagation delay of the pseudo nmos inverter

i found these 2 rules:
tplh=(1.7*C)/(Kp*VDD)

tphl=(1.7*C)/(kn*(1-0.46/r)*VDD)

are these 2 rules right?
and if yes . from where did they come??

and also how do i get the Vol?

Thanks

 

[Vijay.iyer12]

Hello,
well V(OL) is equal Vm, that region where both Pmos and Nmos are in Saturation..

if you want to find Vm simple draw the schematic of an Inverter with ratio PUN/PDN= 2:1

PLot do the DC analysis(sweep the input voltages)... the point where both input and output intersects is the VM its is usually taken as VDD/2. i.e if VDD = 5v than Vm will be equal to 2.5 and so is the VOL.. good luck...

-Iyer