一种非匹配模式恒定跨导的轨到轨运算放大器  

A non matching mode constant transconductance rail to rail operational amplifier

作　　者：刘金朋 刘云涛[1] 刘星晨 方硕 LIU Jinpeng;LIU Yuntao;LIU Xingchen;FANG Shuo(College of Information and Communication Engineering,Harbin Engineering University,Harbin 150001,China)

机构地区：[1]哈尔滨工程大学信息与通信工程学院,黑龙江哈尔滨150001

出　　处：《微电子学与计算机》2024年第8期101-108,共8页Microelectronics & Computer

基　　金：国家自然科学基金重大仪器研制项目(62027814)。

摘　　要：针对传统轨到轨运算放大器输入级跨导恒定受工艺影响,提出了一种非匹配模式低失调恒定跨导轨到轨运算放大器,输入级电路采用最大电流控制法。该运放通过对P输入对管电流的监测,来控制N输入对管的电流,从而实现与工艺无关的恒定跨导的要求。输出级采用折叠式共源共栅的有源负载与AB类控制的输出级结合,提高电压增益,增加电压输出动态范围。运放基于DB Hitek 0.18μm工艺完成电路设计。仿真结果表明:在电源电压为+2.5 V和−2.5 V时,该运放的共模输入范围为−2.5~2.5 V,动态输出范围为−2.5~2.5 V,平均输入失调电压为12.7μV,开环增益为98 dB,相位裕度为73.1°,带宽为73.1 MHz,电源抑制比为90 dB,共模抑制比为95 dB,压摆率为57.1 V/μs,跨导变化率仅为4.9%,满足了恒定跨导的要求。Aiming at the constant transconductance of the input stage of the traditional rail-to-rail operational amplifier is affected by the process,a non-matching mode low offset constant rail-to-rail operational amplifier is proposed,which the input stage circuit adopts the maximum current control method.The operational amplifier controls the current of the N input to the tube by monitoring the current of the P input to the tube,so as to achieve the requirement of constant transconductance independent of the process.The output stage combines the active load of the folded cascode with the output stage of the class AB control to improve the voltage gain and increase the dynamic range of the voltage output.The operational amplifier is designed based on DB Hitek 0.18μm process.The simulation results show that,when the power supply voltage is+2.5 V and−2.5 V,the common-mode input range of the operational amplifier is−2.5-2.5 V,and the dynamic output range is−2.5-2.5 V,the average input offset voltage is 12.7μV,the open-loop gain is 98 dB,the phase margin is 73.1°,and the bandwidth is 73.1 MHz,the power supply rejection ratio is 90 dB and the common mode rejection ratio is 95 dB,the slew rate is 57.1μs,and the transconductance change rate is only 4.9%,meeting the requirement of constant transconductance.

关 键 词：轨到轨 运算放大器 非匹配模式 恒定跨导 

分 类 号：TN722[电子电信—电路与系统]