基于0.18μm SiGe BiCMOS工艺的带宽为2 GHz的高精度可变增益放大器  

DC-2 GHz Bandwidth High-Precision Variable Gain Amplifier Based on 0.18μm BiCMOS Technology

作　　者：谢江滨[1] 秦希[1] 方飞[1] 林楠[1] 洪志良[1] 

机构地区：[1]复旦大学专用集成电路与系统国家重点实验室,上海201203

出　　处：《复旦学报（自然科学版）》2010年第6期745-750,756,共7页Journal of Fudan University：Natural Science

基　　金：Rigol公司资助项目

摘　　要：设计了一个高精度可变增益放大器,采用0.18μm SiGe BiCMOS工艺进行前仿真和后仿真.运用电流反馈型闭环运算放大器获得了高精度的固定电压增益,输出级中加入了共模反馈电路,使得输出共模电压可以由外部控制电压在0.8~1.3 V之间进行调节.另外,先进的补偿网络可以对工艺偏差进行校准,使其带宽达到2 GHz;为了实现增益可调,采用了无源R-xR网络实现步长为2 dB的精确衰减,最终使得增益在数字信号控制下以2 dB步长在-0.93~39.19 dB范围内可调.整个系统结构简单,增益控制方便.A variable gain amplifier（VGA） is designed and simulated for TSMC 0.18μm SiGe BiCMOS process.A current feedback closed loop operational amplifier is adopted to obtain a high-precision fixed gain.Common mode feedback circuit is added to the output stage to make the output common mode voltage variable continuously from 0.8V to 1.3V according to the external control voltage.In addition,an advanced compensation network is embedded to correct the process error.This ensures the bandwidth to be as high as 2GHz.Besides,a R-xR network is used to implement the accurate 2dB/step attenuation.Therefore the whole VGA can be adjusted from 0 dB to 40dB in step of 2dB by digital signals.The system structure is simple and convenient for control.

关 键 词：可变增益放大器 电流反馈型放大器 衰减器 共模反馈 

分 类 号：TN752[电子电信—电路与系统]