An operational amplifier has 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

An operational amplifier has a gain-bandwidth product fT=4 MHzf_T = 4\,\mathrm{MHz}. It is wired as a non-inverting stage with closed-loop gain ACL=40A_{\rm CL} = 40. ((a)) Calculate the closed-loop −3 dB-3\,\mathrm{dB} bandwidth of the stage. ((b)) Calculate the loop gain TT left at a frequency of 200 kHz200\,\mathrm{kHz}, given that at frequencies well above the amplifier's open-loop corner, AOL(f)≈fT/fA_{\rm OL}(f) \approx f_T/f and β=1/ACL\beta = 1/A_{\rm CL}.

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