Open loop pole location bounds for partial positive feedback gain enhancement operational amplifiers

For conventional op amps design open loop poles are usually in the left-half plane. For amplifiers with negative impedance gain enhancement, the open loop pole is adjustable and it can be in the left-half plane or in the right-half plane. In this paper, we justify that it does not require a left-half plane open loop pole for designing a stable close loop amplifier. As a matter of fact, the amplifier exhibits both faster and more accurate settling when the open-loop pole is modestly in the right-half plane. New open loop pole bounds are derived for amplifiers with adjustable open loop pole to guarantee stability and to enhance settling time performance.