应用于包络跟踪的高线性跨导运算放大器的设计  

A High linearity Operational Transconductance Amplifier Used on Envelop Tracking Power Amplifier

作　　者：夏斯青 高怀 

机构地区：[1]苏州市射频功率器件及电路工程技术研究中心,江苏苏州215123

出　　处：《电子器件》2012年第5期530-534,共5页Chinese Journal of Electron Devices

基　　金：江苏省科技厅科技支撑计划项目(SBE201100180)

摘　　要：设计了一款改进的基于交叉耦合结构的跨导运算放大器(OTA)。设计和分析过程中依据严格的理论推导,新结构在高输入摆幅下线性度得到明显优化,当输入为2V@5MHz正弦波时,谐波总量从0.7%降至0.3%,并成功应用于包络跟踪功率放大器。仿真测试基于CSMC 0.5μm CMOS工艺,仿真结果表明二到五次谐波分量总和从传统OTA的-40 dB降低到-52 dB,同时在VSS系统联合仿真平台上,用15 MHz带宽的OFDM调制信号测试星座图,其聚敛性也得到了明显优化,矢量误差从4.7%降至3.6%。This paper presents a new construction of operational transconductance amplifier（OTA）which is based on traditional 4-cell cross-coupled OTA.Unsymmetrical of MOS and error of current caused by mirror currents would make more and more harmonic produced by OTA.Such situation will be more serious when the input become larger.So here provides a new construction by citing a differential pairs into the input stage.When the input is sine signals for 2V@15MHz,the proportion of the harmonic component would be decreased from 0.7% to 0.3%.The way has been testified by mathematical deduce,in the base of 4-cell cross-coupled OTA.The linearity has been improved obviously and proved in the simulation of CSMC 0.5 CMOS craft.Meanwhile it has applied on the envelop amplifier,the totally extra component that includes second to fifth harmonic is reduced from-40 dB to-52 dB.This work utilized the VSS of AWR to simulate I-Q chart which was driven by a 15 MHz bandwidth of OFDM modulation signals from the chart we could find amass performance got a high improvement,which could be read by the EVM,older vision was 4.7% but this work had been reduced to 3.6%.

关 键 词：跨导运算放大器 交叉耦合结构 线性度优化 

分 类 号：TN432.1[电子电信—微电子学与固体电子学]