Universal basis for ranking small-signal aspects of compensation techniques for operational amplifiers

摘要

A multi-pole gain-bandwidth theorem sets an upper bound to the bandwidth that can be achieved with specified DC gain and external load capacitance, for a given selection of transistors and operating points. A product of the poles and zeros is constrained by ∏(gm/C) evaluated over the forward-path active devices. Most practical compensation techniques degrade the actual bandwidth, by factors which the paper explores in detail; depending on the circuit topology, some compensating capacitors can add to the intrinsic device capacitances. A few techniques achieve the ideal.