Residual offset optimization for a continuous time autozero amplifier

In this paper, a continuous time autozero (AZ) amplifier topology is presented. To improve offset cancellation, a fully differential internal AZ loop is used. An analytical model is developed for estimating the residual offset during both operation phases; taking into account the main offset contributions: base and cancellation amplifiers offset voltages and respectively charge injection. The design considerations for achieving optimal residual offset are presented.