A new modeling and optimization of gain-boosted cascode amplifier for high-speed and low-voltage applications

Abstract

Because of limited output swing, the basic structure of a gain-boosted cascode amplifier (GBCA) cannot be used to design a low-voltage operational amplifier. In this paper, we investigate the design of a high-swing GBCA, and find the optimum bandwidth for the boosting or feedback amplifier. This bandwidth eliminates the slow-settling component in the step response, prevents the gain-boosting loop from being unstable, and results in the shortest settling time. Finally, we present a very high-speed and high-swing amplifier suitable for low-voltage applications.