A fully differential CMOS operational amplifier implemented with MOS gain boosting technique

This thesis investigates the gain boosting technique proposed by K.Bult and G. Geelen [9]. An improved cascode circuit that combines both high gain and high speed is developed. Using this cascode circuit, a high performance fully differential operational amplifier is designed. A prototype of the cascode circuit and operational amplifier was fabricated in a 2 |im n-well CMOS technology. Simulation results indicate that the cascode circuit has at least 100 MQ output impedance, while the amplifier has an open loop gain of 98 dB and a unity gain frequency of 17 MHz for 10 pF load capacitor.