Vdd min = Vt,n + |Vt,p| ?

[kweijun]

I've read this in a CMOS book. It stated that the minimum supply voltage, Vdd min, in order for a CMOS inverter to work is equal to nMOS threshold voltage, Vt,n + pMOS threshold voltage, Vt,p.

The question is,
Since only one of the MOS in a CMOS inverter will conduct at one time, the Vdd min should be ≥ Vt,n right?

Please advise. Thanks

 

[Davood Amerion]

see

 

[jackson_peng]

at least one MOSFET should work in linear region, otherwise how could it recognize the output logic value.
so the miminum value is right.