Design Of The Technology-Independent Operational Amplifier Based On Negative-Impedence Technology

Based on the Analog Integrated Circuit Design Principles and BSIM models, this paper analyzed the performance parameters of CMOS fully differential operational amplifier in HSPICE 0.25um and 0.18um CMOS processes, respectively. It also designed a technology-independent CMOS fully operational amplifier by small channel length devices, as well as the bias circuit.Firstly, by studying the DC bias, DC gain, match, noise and the bandwidth conditions of the circuit, it settled the influences of channel length of devices on performance parameters. It also normalized the changes of technology-dependent parameters by comparing the advantages and disadvantages of several typical operational amplifiers.Then, constructed the constant gain CMOS operational amplifier and verified the performance by simulating in HSPICE in 0.25um and 0.18um processes. It designed the bulk-driving bias circuit to generate technology-independent bias current biasing amplifier. CMFB and Miller Compensation were also introduced in to keep the amplifier stable.Finally, based on the previous analyses, this paper modified the architecture of the amplifier to improve performance parameters: gain, UGBW and phase margin. It analyzed the compensation approach, slew rate, input referred noise, ICMR and PSRR of the amplifier and generated constant UGBW, constant phase margin while keeping high gain.The simulation results demonstrated that the amplifier represented in this paper can achieve, sometimes even exceed, the respected performance requirements. This two stage CMOS fully differential amplifier has an open-loop gain of 92dB, UGBW 60MHz, phase margin 89 degrees and power dissipation 2.1mW. It can be used in low voltage low power ADC, DAC, buffer etc. Additionally, this technique can also used in video receiving, digits processing and other essential electronic technologies.