Question

Find the ft  required for internally compensated op amps to be used in the implementation of the closed loop amplifiers with dc gain of -2 V/V and 3db bandwidth of 10 MHz?

(a) 7.5 MHz

(b) 15 MHz

(c) 22.5 MHz

(d) 30 MHz

This question was posed to me in quiz.

My doubt is from Effect of Finite Open-Loop gain and Bandwidth on Circuit Performance in division Operational Amplifiers of Electronic Devices & Circuits

Answer 1

The correct option is (d) 30 MHz

Explanation: ^-R2 ⁄ R1 = -2^V⁄V

f3db = 10 MHZ ft = 10 MHZ(2 + 1) = 30 MHZ.