An operational amplifier's datasheet quotes a gain-bandwidth product

PHYSICS · Multi-part · Fermi University Physics · Electronics, Instrumentation & Communication · Feedback, operational amplifiers and analogue signal processing · Feedback, operational amplifiers and analogue signal processing

Electronics for Measurement, Ch The operational amplifier and negative feedback

Problem

f_T = 4\,\mathrm{MHz}

. It is built first into a non-inverting stage of closed-loop gain

A_{\rm CL} = 20

, and then rebuilt with different resistors into a non-inverting stage of closed-loop gain

A_{\rm CL} = 200

. ((a)) Predict the

-3\,\mathrm{dB}

closed-loop bandwidth of each stage, before either is put on the bench. ((b)) Both stages are then measured. Should the measured bandwidths be expected to equal the predictions of part (a) exactly? Name one effect that could make a measured value lower than predicted and one that could make it higher.

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