Continuous-time common-mode feedback networks for fully-differential amplifiers: a comparative study

Suitable figures of merit to compare different common-mode feedback (CMFB) networks are deduced. They allow evaluation of the conversion gain or linear interaction, relative performance, and nonlinear interaction between common-mode and differential-mode loops in any fully differential one-stage output compensated amplifier. Three often used CMFB loops, based on different operation principles, are classified according to these figures of merit.< >