For an NMOS transistor for which Vt 1V operating with Vgs i

For an NMOS transistor, for which V_t = 1V, operating with V_gs in the range of 1.5V to 4V, what is the largest value of V_ds for which the channel remains continuous?

Solution

Vgs > Vt # Vgs so the channel is always present

then for the channel to remain opened at the drain end

Vds < Vgs - Vt (triode)

so to find Vds max we have to use smallest Vgs

Vds_max < 1.5 - 1 = 0.5 v