D5.3 A circuit designer intending to operate a MOSFET in saturation is considering the effect of changing the device dimensions and operating voltages on the drain current iD. Specifically, by what factor does iD change in each of the following cases?
(a) The channel length is doubled.
(b) The channel width is doubled.
(c) The overdrive voltage is doubled.
(d) The drain-to-source voltage is doubled.
(e) Changes (a), (b), (c), and (d) are made simultaneously.
Which of these cases might cause the MOSFET to leave the saturation region?
0.5; 2; 4; no change; 4; case (c) if vDS is smaller than 2vOV