Modeling and optimization of fast-settling time gain-boosted cascode CMOS amplifiers

Settling time is a very critical performance requirement for CMOS amplifiers in switched-capacitor circuits. The settling mechanism of gain-boosted amplifiers is very complicated. In this paper, the small-signal model for the gain-boosted cascode amplifier is analyzed. The gain bandwidth product and phase margin optimum values for the gain boosting amplifiers used inside gain-boosted cascode amplifiers are given for the minimum settling time. Finally, we present a low-voltage, high-gain and fast-settling time CMOS amplifier.