Question

If a gain of at least 5 V/V is needed, what value of gm is required?

(a) 0.1 mA/V

(b) 0.2 mA/V

(c) 0.4 mA/V

(d) 0.8 mA/V

This question was addressed to me in an interview.

This intriguing question comes from MOSFET in Small Signal Operation topic in division MOS Field Effect Transistors (MOSFETs) of Electronic Devices & Circuits

Answer 1

Correct choice is (a) 0.1 mA/V

The best explanation: gmRd = 5 or gm= 5/50 mA/V.