Inverter - 4 - Trip Point for Short Channel Device Inverter

[@Rahul-hq8gl]

How VDS will decrease if we increase the wp value

[@akashekhar]

Because the device resistance will decrease.

[@i_latebloomer101]

At 21:14 how VDS is giving me the current ?

[@Abhish1_7]

Why at 26:25, the sign is taken as negative?

[@socialogic9777]

If Vm-Vtn is positive --> RHS should also be positive.
Vm will always be less that VDD + Vtp, as Vm indicates trip point, in all plausible scenarios trip point will be closer to VDD and will never exceed VDD + Vtp(Vtp < 0 && Vtp = -Vtn).
Vm can be brought closer to VDD + Vtp by increasing Wp, but at Vin = VDD + Vtp, PMOS will be off --> Idsp = 0 --> Vo = 0 to make Idsn = 0. Trip point should occur before this happens.
To make RHS positive for r>0, coefficient of RHS should be negative.

[@Rahul-hq8gl]

@@socialogic9777 why Vm - Vtn should be +ve

[@socialogic9777]

@@Rahul-hq8gl because Vm will always be greater than Vtn
Vm - Switching threshold(both nmos and pmos saturation)
Vtn - NMOS threshold( voltage at which nmos enters saturation while pmos changes from linear to saturation)
The switching threshold of the CMOS inverter will always be greater than NMOS threshold( visible in the VTC too)

[@sachinkumar-xl1nq]

@@socialogic9777 can you plz tell me that in velocity saturation, which current equation should we use linear or saturation form?

[@akashekhar]

@@sachinkumar-xl1nq The current equation for velocity saturation is similar for as in linear region, but we have to substitute the value for Vd(sat) instead of Vds.

[@acatlikeafish]

9:52 15:59 24:05 27:30