Analysis and Design of Fully Differential Gain-Boosted Op-amp for 14bit 100MS/s Pipelined Analog-to-Digital Converter

摘要

This paper presents the analysis and design of high speed, high gain fully differential operational amplifier (op-amp). The op-amp is designed for sample and hold circuit of 14 bit 100MS/s pipelined analog-to-digital converter (ADC). Both the main op-amp and the boosting op-amp are fully differential folded-cascode. The main op-amp has a switched capacitance common mode feedback circuit. The boosting op-amp is connected as a follower. The op-amp is designed in 0.18μm CMOS process with 3.0V power supply. Spectre simulation shows that the op-amp has the DC gain of 112dB and the unity gain bandwidth of 1.15GHz.