CMOS可变增益放大器设计概述.pdf

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第 35 卷第 6 期微电子学 Vol 35, № 6
2005年 12月 M icroelectron ics Dec 2005
文章编号: 1004 3365 (2005) 06 0612 06
CMOS可变增益放大器设计概述
王自强 1 , 池保勇 2 , 王志华 2
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(1. 清华大学电子工程系, 北京 100084; 2. 清华大学微电子所, 北京 100084)

摘要: 可变增益放大器是模拟单元电路之一,起着变化增益、调整信号动态范围、稳定信号功率
的作用。文章综述了 CMOS集成可变增益放大器的研究情况;给出了可变增益放大器的定义、应
用、分类和主要指标,描述了多种开环和闭环放大器的结构,分析了相应的增益控制方法及其优缺
点;说明了在 CMOS工艺下实现放大器增益按指数变化的几种途径。最后,介绍了用于无线数字通
信,具有宽带、高线性、低电源电压等高性能可变增益放大器的设计实例。
关键词: 放大器; 可变增益放大器; 可编程增益放大器; 指数增益控制
中图分类号: TN72; TN432 文献标识码: A

An O verv iew of CMO S Var iable Ga in Am plif iers
WANG Zi qiang1 , CH IBao yong2 , WANG Zhi hua2
(1. Dept. of Elec. Engineer. , Tsinghua Univ. , B eijing, 100084; 2. Insti. of M icroelec. , Tsinghua Univ. , B eijing, 100084, P. R. China)

Abstract: Variable gain amp lifier (VGA) is an analog circuit, which varies gain, adjusts signal dynam ic range and sta
bilizes signal power. An overview of CMOS integrated variable gain amp lifiers is made. The definition of VGA and its func
tion, classification and specifications are elaborated. D ifferent open and closed loop VGA’s are described, and the advan
tages and disadvantages of gain control strategies are analyzed. App roaches to achieving exponential gain in CMOS technolo
gy are exp lained. Finally, examp les of high performance VGA ’s used in wireless munication are introdu