Pinch off voltage vs sturation voltage

[Tesla96]

Hello,

Could anyone explain to me the difference between saturation voltage and pinch off voltage.
The condition to operate mosfets in saturation is to have Vds voltage beyond saturation voltage. Since the channel is pinched off at a lower voltage (V pinch off) why this condition (Vds>Vds,sat => sat.) states?

Thanks in advance

 

[sutapanaki]

In old square low terminology, the Vd voltage where the channel pinches off (that is the voltage where the drain is Vth above gate for NMOS) is where the saturation starts. If you keep increasing the drain voltage wrt to gate, the NMOS is going deeper in saturation.

 

[crutschow]

Note that, unlike a BJT, the saturation region in a MOSFET is where it is in the active (constant current) region, not fully turned on.

 

[dick_freebird]

There is a transition region between subthreshold
and saturation regions, and if you are after the benefits
of saturation-region operation (high Rout primarily)
you want to stay out of the suburbs. That means
comfortably above VT, for Vds.