| With the development of technology and the Internet of things,people’s life is becoming more and more digital,but in fact,the natural signals they come into contact with in life are continuous analog signals,even if the application is biased toward fast and simple digitization,but the analogy-to-digital converter is still a very important bridge module in the signal application,because the SAR ADC is good at simple structure,PVT insensitivity and small power consumption,which is also have strong robustness,compared to other structures of the ADC.Although the development of SAR ADC was limited by the medium-low speed and medium-low precision before,with the development of recent years,researchers have gradually broken through the limitations of traditional SAR ADC in speed and accuracy.For applications such as medical and wearable devices,SAR ADC become a research hotpot again with a high precision and low power consumption.In this thesis,the key modules and error sources of high precision SAR ADC are analyzed theoretically.By analyzing the high gain of the traditional static comparator structure when the transconductance is equal,the theoretical and practical feasibility of the high gain and low bandwidth comparator is studied.By improving the segmental capacitor switching array and monotone capacitor array,a hybrid capacitor switching array is optimized,which reduces the serious common-mode voltage change caused by the traditional monotone CDAC switching.In the circuit simulation,the significant bit is14.07 bits,SNR is 87.368 d B,and SFDR is 101.347 d Bc.A simulation anti-aliasing filter with single terminal input to differential output and a bandgap reference voltage with temperature coefficient of 7.76ppm/℃ are designed. |
