OPTIMIZATION OF CHOPPER AMPLIFIERS FOR SPEED AND GAIN

This paper presents design techniques to optimize the performance of chopper-stabilized ac-coupled CMOS inverter amplifiers. These amplifiers are used as comparators in high-speed flash analog-to-digital converters extensively [1]-[3]. For any given process technology, as the required conversion speed and resolution are increased, the amplifiers are required to increase their conversion speed and resolution, and to have higher switching speed as well as higher gain. Although these two requirements are in general contradictory, they can be optimized by proper design. In this paper, analytical expressions are derived which can be used to optimize these amplifiers. The results obtained from these analytical expressions and SPICE simulations agree well.