Design Of High Figure Of Merit Amplifiers

Operational amplifier is one of the most widely used linear circuits.It is also a very important basic module in analog and mixed-signal circuit systems.It plays a key role in the realization of high performance circuit systems.Due to the inherent constraints between various performance,the implementation of the high performance amplifiers under low power constraints is valuable.Therefore,according to the key indicators of a particular amplifier,the figure of merit?FoM?is defined to describe the overall performance of the amplifier.Based on the TSMC 0.35?m CMOS process,the parameters optimization and simulation verification of two high FoM amplifiers were completed by using simulation tools such as Cadence and HSpice.An equivalent transimpedance amplifying circuit,composed of a transimpedance gain stage and a push-pull voltage gain stage,is used for current amplifying and current-voltage conversion.A parallel current negative feedback and a gate control structure are adopted to detect photon-generated current under 77K low temperature;based on the classical transconductance amplifier,the cross-coupling nonlinear and dynamic tail current control structure is adopted to realize the fast transient response voltage follower.Through modeling and g_m/i_d design methodology,finally completed two high FoM amplifiers for different applications.In this thesis,the two amplifiers are fabricated.The test results show that the transimpedance amplifier works normally at 77K,can detect the photon-generated current,and proposes a feasible test scheme.The transconductance amplifier achieves the open-loop transconductance gain of 58dB,the unity gain bandwidth of 2.7MHz,the phase margin of 45deg,the slew rate of 14V/?s.The FoM_DY is 22,FoM_ACC is 4V^-1 under 25?A quiescent current,40pF load capacitance and 3.3V voltage environment.The thesis analyzes the main reasons for the degradation of the performance of the two circuits,and proposes a targeted design strategy for improvement.