一种高性能数控VGA设计  

Design of high⁃performance digital control VGA

作　　者：张瑜 俞阳 蒋颖丹 吴舒桐 魏敬和 ZHANG Yu;YU Yang;JIANG Yingdan;WU Shutong;WEI Jinghe(China Electronics Technology Group Corporation No.58 Research Institute,Wuxi 214026,China;National Key Laboratory of Integrated Circuits and Microsystems,Wuxi 214026,China)

机构地区：[1]中国电子科技集团公司第五十八研究所,江苏无锡214026 [2]集成电路与微系统全国重点实验室,江苏无锡214026

出　　处：《现代电子技术》2024年第24期8-12,共5页Modern Electronics Technique

基　　金：江苏省自然科学基金项目(BK20211041)。

摘　　要：为了满足高灵敏度、高速接收机的要求,设计一种新型高性能数控可变增益放大器(VGA)。电路模块主要包括前置放大器、增益跨导单元和输出放大器。通过8位增益控制字的最高有效位选通前置放大器,实现高低两段增益调节范围,剩余7位增益控制字实现45 dB的增益调节范围。利用SiGe BiCMOS工艺的高截止频率和低谐波特性,结合负反馈法,实现了高线性度。基于电流舵结构设计跨导单元,结合宽带跨阻放大器,实现了宽增益调节范围。采用Cadence软件进行仿真,经过流片验证,实现了-25~20 dB、-11~34 dB两段增益调节范围,以及35.23 dBm OIP3的高性能数控VGA。所设计的增益放大器可用于中频采样接收机、射频/中频增益级、差分ADC驱动等接收前端电路。In order to meet the requirements of high-speed and high-sensitivity receivers,a new type of high-performance digital control variable gain amplifier(VGA)is designed.The circuit mainly includes the preamplifier,gain transconductance unit,and output amplifier.The preamplifier picks high-gain or low-gain mode by means of the most significant bit(MSB)of the 8-bit gain control word.The remaining 7-bit gain control word can realize the gain adjustment range of 45 dB.By utilizing the high cutoff frequency and low harmonic characteristics of SiGe BiCMOS technology,the high linearity is designed and implemented by combining with negative feedback method.The transconductance unit based on current steering structure is designed to realize the wide gain adjustment range by combining with a broadband transimpedance amplifier.The simulation experiments were conducted by means of Cadence software,two gain adjustment ranges of-25~20 dB and-11~34 dB were realized after chip verification,as well as a high-performance digital control VGA with 35.23 dBm OIP3.The designed VGA can be used in front-end circuits of receiver such as intermediate frequency sampling receivers,IF/RF frequency gain stages,and differential analog-to-digital converter(ADC)drivers.

关 键 词：可变增益放大器 数控 增益控制 跨导增益 前置放大器 高线性度 最高有效位 

分 类 号：TN722-34[电子电信—电路与系统]