A GAIN BOOSTED FOLDED CASCODE USING TELESCOPIC BOOSTING AMPLIFIERS WITH SWITCHED CAPACITOR INPUT LEVEL SHIFTERS

摘要

This paper describes a single stage fully differential foldedcascode operational transconductance amplifier (OTA)with fully differential gain boosting amplifiers designed in1.2 VDC 130nm CMOS process technology. The amplifieris the driver for the analog to digital converter (ADC) ofa blood pressure sensing medical implant [1] which useswireless power transmission as its energy source [2]. Themedical implant’s design specifications require an amplifierwith wide output swing, high accuracy, and the bandwidthto drive a differential 5 pF load at 4 ksps with minimumpower consumption. The gain boosting amplifiers are telescopiccascoded amplifiers, which, by their design, have aninput and output common mode voltage relationship whichis opposite to what is needed for a gain boosted cascodeconfiguration. To correct for this, a method for DC shiftingthe amplifier’s input voltage using a switched capacitornetwork is presented.