ROBUST ANALOG VLSI CIRCUIT DESIGN

Abstract

Variation in transistor characteristics is increasing as CMOS transistors are scaled to nanometer feature sizes. In analog integrated circuits, the variability of identically designed devices plays an important role since it directly affects the attainable precision. An operational amplifier is one of the most basic components in analog integrated circuit design. Random device mismatch creates input referred offset voltage in the op amp which limits the overall performance of the system in many cases. In this work, chopper stabilization is applied to the amplifier to reduce the input referred offset voltage. The chopper stabilized op amp is used to build a bandgap reference voltage. In simulations, chopper stabilization improved the accuracy of the bandgap reference voltage from +/- 11.62% (3o variation due to random mismatch only) to less than +/- 0.02%. All the circuits in this work are implemented using Intel's 32 nm CMOS process