Modified Model for Settling Behavior of Operational Amplifiers in Nanoscale CMOS

An accurate time-domain model for the settling behavior of folded-cascode operational amplifiers is presented. Using a velocity-saturation model for MOS transistors makes the proposed model suitable for nanoscale CMOS technologies. Both linear and nonlinear settling regimes and their combination are considered. Transistor-level HSPICE simulation results of a fully differential single-stage folded-cascode amplifier using BSIM4v3 models of a standard 90-nm CMOS process are presented to verify the accuracy of the proposed models.