Research And Design Of Novel CMOS High Performance Current Differencing Transconductance Amplifier

Since the semiconductor and communication industries continue to impose increasingly greater demands on the performance of integrated circuit,state-of-the-art analog integrated circuit design is recently receiving a tremendous boost from the development and application of current-mode approaches,which are rapidly superseding traditional voltage-mode techniques.The current-mode circuit exhibits various advantages than the voltage-mode circuit,such as lower DC supply voltage and power cons?mption,wider bandwidth,larger dynamic range and so on.It has also been provided attractive solutions for many analog circuit and systems.Thus,the significant of designing high performance current-mode devices and developing various current-model analog application circuits are obvious.Current differencing transconductance amplifier(CDTA)is a new current-mode active device and has potentially broad application in the field of analog signal processing including high frequency continuous-time analog filter,oscillator and high-speed rectifier.But with the rapid development of such a wide variety of CMOS analog&digital mixed-signal integrated circuit,the design of analog integrated circuits should meet the CMOS process with a low operating supply voltage and high frequency bandwidth as soon as possible.This thesis analyses in detail the research status and basic principle of CDTA,the realization methods of CDTA are also studied.The research work of thesis brings forward novel high performance CMOS CDTA circuits and their application circuits,and they are as follows:1.A novel±0.8V high performance voltage-tunable CMOS CDTA is designed.By using low-voltage cascaded current mirror active resistance compensation techniques,the proposed CDTA circuit provides a wide frequency bandwidth,high current tracking precision as well as large output impedances.The linear tunable G_M of CDTA is designed with use of linear composite MOSFETs as basic cells in the circuit.Combining these two approaches,several design concerns is studied:impedance characteristic,tracking errors,offset and linearity,as well as noise.Cadence Virtuoso Analog Design Environment using GlobalFoundries'0.18?m CMOS process is used to develop the CDTA circuit and verify with simulations of schematic.Cadence Spectre simulating results with±0.8V DC supply voltage reveal that the-3dB bandwidth of proposed CDTA is approximately 1GHz.In addition,the transconductance gain can be linearly varied from 286.9?S to 852.1?S.A fully differential band-pass filter for high speed system is also chosen as an example to confirm the high performance of proposed circuit as well.The performance makes it a proper candidate for low-voltage high-frequency analog signal processing applications.2.A new active device,namely digitally programmable CDTA is presented.B ased on the voltage-tunable CDTA circuit,the digitally programmable CDTA is built around a lot of programmable current mirror arrays and linear tunable transconductors,which contains separate analog and digital tuning features.The proposed circuit can be widely used in field of analog&digital mixed-signal processing,and has greatly practicalit y value.Moreover,a CDTA-based mixed-signal modulation circuit with two fixed-value capacitors and two grounded resistors is proposed and analyzed.The proposed circuit can be configured to perform the following signal modulation techniques:amplitude modulation(AM),frequency modulation(FM),amplitude shift keying(ASK),frequency shift keying(FSK),phase shift keying(PSK),and quadrature amplitude modulation(QAM).Cadence Virtuoso Analog Design Environment using GlobalFoundries'0.18?m CMOS process is used to develop the generator circuit and verify the theory with some simulations.The results from simulation s prove that the designed circuit has good reliability and practicality.