Fast-settling CMOS two-stage operational transconductance amplifiers and their systematic design

Compared to single-stage OTAs, two-stage OTAs have higher gain and output swing, but more poles and zeros and thus have more complex settling behavior. Two structures of two-stage OTAs that have good settling performance are introduced. By analyzing the settling behavior of the third order system, a set of poles and zeros parameters are extracted. A design procedure for minimum settling time of these two OTAs is described. Finally two design examples for minimum settling time are presented. These high-speed OTAs are suitable for high-speed switched-capacitor applications.