【作者】 邓红辉； 尹勇生； 高明伦；

【Author】 Deng Honghui Yin Yongsheng Gao Minglun (Institute of VLSI design,Hefei University of Technology,Hefei 230009 China)

【机构】 合肥工业大学电子科学与应用物理学院微电子设计研究所；

【摘要】 设计了一种1.2V低功耗、恒跨导、全摆幅的CMOS轨对轨运放,输入级采用最大电流选择电路实现跨导的恒定,并使跨导达到传统输入级的两倍。输出级采用改进的反馈式AB类输出级,使输出晶体管的电流得到精确控制且不受工艺的影响,并使输出达到轨对轨全摆幅。基于SMIC 0.18um工艺模型,利用Hspice软件对电路进行仿真,仿真结果表明:当电路驱动2pF的负载电容以及10kΩ的负载电阻时,直流增益达到81.7dB,单位增益带宽为2.63MHz,相位裕度为60.5°;共模输入范围达到轨对轨,在整个共模输入变化范围内跨导变化率仅为2.8%;输出摆幅达到轨对轨全摆幅;在1.2V的低电压下电路正常工作,静态功耗仅为83uW。更多还原

【Abstract】 A 1.2V low-power Rail-to-Rail input/output CMOS operational amplifier with constant-gm is designed in this paper.A maximum current selection circuit is used in the input stage to achieve constant-gm which is the twice of the traditional input stage’s. An improved feedback class AB output stage is used to ensure that the current of the output transistors to be controlled precisely and is not affected by the technology,while the output swing achieves rail-to-rail.The circuit is simulated by using SMIC 0.18um process model and Hspice simulation software.The simulation results show that the DC gain is 81.7dB,the unity gain bandwidth is 2.63MHz, and the phase margin is 60.5°when the circuit driving a load capacitance of 2pF and a load resistance of 10kΩ.The input common-mode range reaches rail to rail,and the variation of the gm is only 2.8%;The output swing reaches rail to rail;The circuit operates normally in a low voltage of 1.2V,and the static power consumption is only 83uW.更多还原