复旦大学：《集成电路工程》教学资源（硕士士学位论文）CMOS宽带可变增益低噪声放大器的设计.pdf_大学文库

目录目录··························································································I 图目录························································································III 表目录························································································ V 摘要·························································································1 Abstract······················································································3 第一章概述················································································5 1.1 移动数字电视调谐器···························································5 1.2 宽带可变增益低噪声放大器··················································6 1.3 研究内容及贡献·································································8 1.4 论文组织结构····································································8 第二章常见低噪声放大器···························································· 11 2.1 主要性能参数·································································· 11 2.1.1 输入反射损耗系数··················································· 11 2.1.2 噪声系数······························································· 11 2.1.3 线性度·································································· 12 2.1.4 级联的噪声和线性度················································ 12 2.1.5 灵敏度·································································· 13 2.2 传统结构的低噪声放大器··················································· 13 2.2.1 共源结构······························································· 14 2.2.2 共栅结构······························································· 15 2.2.3 电阻反馈结构························································· 15 2.3 跨导增强和电容交叉耦合低噪声放大器································· 16 2.4 噪声抵消低噪声放大器······················································ 18 第三章有源负反馈低噪声放大器··················································· 23 3.1 电压增益和输入阻抗匹配··················································· 23 3.2 噪声系数········································································ 25 3.2.1 噪声因子的计算······················································ 25 3.2.2 噪声因子的优化考虑················································ 27 3.2.3 输入阻抗不匹配对噪声系数的影响······························ 28 3.3 线性度··········································································· 29 3.4 稳定性··········································································· 32 第四章可变增益低噪声放大器的设计············································· 33 4.1 前言·············································································· 33 4.2 高增益模块····································································· 34

4.2.1 偏置电路的考虑······················································ 34 4.2.2 高增益模块 2-dB 增益台阶 ········································ 37 4.3 电阻衰减器····································································· 38 4.3.1 衰减器增益···························································· 38 4.3.2 衰减器的噪声因子··················································· 41 4.4 中间增益········································································ 42 4.5 完整的可变增益低噪声放大器············································· 44 第五章芯片设计和仿真结果 ·························································· 47 5.1 版图设计········································································ 47 5.1.1 低噪声放大器的版图设计·········································· 47 5.1.2 电阻衰减器的版图设计············································· 49 5.1.3 整体版图的布局······················································ 51 5.2 后仿真结果····································································· 51 5.2.1 最高增益低噪声放大器的仿真结果······························ 51 5.2.2 可变增益低噪声放大器的 S11 ····································· 53 5.2.3 可变增益低噪声放大器的增益···································· 54 5.2.4 可变增益低噪声放大器的噪声系数······························ 55 5.2.5 可变增益低噪声放大器的 IIP3 ···································· 56 5.3 设计小结········································································ 57 第六章总结与展望 ······································································ 59 6.1 总结·············································································· 59 6.2 展望·············································································· 59 参考文献···················································································· 61 致谢·························································································· 69

图目录图 1-1 直接下变频结构调谐器结构 ····················································5 图 1-2 (a)多个窄带组成宽带；(b)单个宽带 ··········································7 图 2-1 MOS 管的沟道噪声····························································· 11 图 2-2 电视调谐器的简化级联结构 ·················································· 13 图 2-3 共源结构 ·········································································· 14 图 2-4 共栅结构 ·········································································· 15 图 2-5 电阻反馈结构 ···································································· 16 图 2-6 跨导增强共栅低噪声放大器 ·················································· 16 图 2-7 电容交叉耦合差分低噪声放大器 ············································ 17 图 2-8 电阻负反馈匹配电路的(a)噪声和(b)有用信号 ···························· 18 图 2-9 噪声抵消低噪声放大器示意图 ··············································· 18 图 2-10 宽带噪声抵消低噪声放大器················································· 19 图 2-11 噪声抵消技术的另一种实现················································· 21 图 3-1 有源负反馈低噪声放大器 ····················································· 23 图 3-2 计算输入阻抗的小信号等效电路图 ········································· 23 图 3-3 不同增益对应的 RF和 gm2的值·············································· 24 图 3-4 计算噪声电流 in1到输出电压 vn,out的传输函数的等效小信号电路图 25 图 3-5 输入阻抗对噪声系数的影响 ·················································· 28 图 3-6 低噪声放大器中非线性失真的产生 ········································· 29 图 3-7 对不同电压增益 AV，IIP3随 RF的变化关系 ······························ 31 图 4-1 可变增益低噪声放大器的两种实现方式 ··································· 33 图 4-2 衰减后再放大的可变增益低噪声放大器结构 ····························· 33 图 4-3 可变增益的低噪声放大器 ····················································· 35 图 4-4 共栅管栅极偏置电压开关的实现 ············································ 35 图 4-5 应用恒定跨导偏置技术产生偏置电流 ······································ 36 图 4-6 低噪声放大器的偏置电路 ····················································· 36 图 4-7 可变增益电阻衰减器 ··························································· 39 图 4-8 电阻衰减器中的开关 ··························································· 40 图 4-9 电阻衰减器的噪声因子 ························································ 41 图 4-10 传统 R-2R 电阻衰减器 ······················································· 42 图 4-11 电阻衰减器的噪声系数与电压增益的关系······························· 42 图 4-12 att 与 lna_mg 串联实现放大器的中间增益 ······························ 42 图 4-13 完整的可变增益低噪声放大器·············································· 45 图 5-1 lna_uhf 的版图··································································· 48

图 5-2 lna_vhf 的版图··································································· 49 图 5-3 att_uhf 的版图 ··································································· 49 图 5-4 att_vhf 的版图 ··································································· 50 图 5-5 整体可变增益低噪声放大器的版图 ········································· 50 图 5-6 UHF 最高增益模式低噪声放大器的增益、NF、S11 ···················· 51 图 5-7 VHF 最高增益模式低噪声放大器的增益、NF、S11····················· 52 图 5-8 UHF 最高增益模式 IIP3仿真结果 ··········································· 52 图 5-9 VHF 最高增益模式 IIP3仿真结果············································ 53 图 5-10 UHF 频段 660 MHz 处 S11随增益的变化································ 53 图 5-11 VHF 频段 150 MHz 处 S11随增益的变化 ································ 54 图 5-12 UHF 的增益及增益台阶······················································ 55 图 5-13 VHF 的增益及增益台阶······················································ 55 图 5-14 UHF 频段 660 MHz 处噪声系数随增益的变化 ························· 56 图 5-15 VHF 频段 150 MHz 处噪声系数随增益的变化 ························· 56 图 5-16 UHF 频段 IIP3随增益的变化················································ 57 图 5-17 VHF 频段 IIP3随增益的变化················································ 57

摘要在过去的数十年间，许多发达国家已经完成了从模拟电视广播到数字电视广播的转变，如美国、西欧、韩国和日本等，与此同时，南美、中国及其他北美国家也已经开始了数字电视的部署工作。世界上许多国家都积极制定了各自的数字电视广播标准，针对手持多媒体设备的视频接收越来越受到重视。为了能够在不同地区用同样的设备可以提供相同的服务，支持多协议多标准的宽带接收机是最好的解决方案。本文详细介绍了应用于数字电视调谐器的宽带可变增益低噪声放大器的设计。首先，根据现存的数字电视广播标准及多标准多频带调谐器的指标要求，确定了宽带可变增益低噪声放大器的性能指标，接着介绍了低噪声放大器的基本概念和最常见的低噪声放大器结构，分析并总结各种结构的核心思想和优缺点。其次，着重分析了有源负反馈结构的低噪声放大器，包括其电压放大倍数、输入反射损耗、噪声系数、输入三阶交调点和稳定性等内容。然后，以有源负反馈结构为可变增益低噪声放大器的高增益放大模块，并采用恒定跨导偏置技术，结合无源电阻分压衰减器构建出完整的CMOS宽带可变增益低噪声放大器；同时，分析低噪声放大器的增益及增益台阶的稳定、噪声系数和输入三阶交调点等设计指标。最后，完成整体可变增益低噪声放大器的版图设计和后仿真。仿真结果表明，在VHF(50~250MHz)和UHF(470~860MHz)频段，最高增益可分别达到22dB 和20dB;最高增益模式下，噪声系数可分别低至1.16dB和1.41dB;输入三阶交调点分别为+0.5dBm和+1dBm:输入反射损耗保持在-11dB和-8dB以下。电源电压为1.8V时，在VHF和UHF工作频段下电路消耗的电流都小于8 mA. 关键词：数字电视调谐器、宽带可变增益低噪声放大器、电阻衰减器、噪声系数、线性度中图分类号：TN432 1

1 摘要在过去的数十年间，许多发达国家已经完成了从模拟电视广播到数字电视广播的转变，如美国、西欧、韩国和日本等，与此同时，南美、中国及其他北美国家也已经开始了数字电视的部署工作。世界上许多国家都积极制定了各自的数字电视广播标准，针对手持多媒体设备的视频接收越来越受到重视。为了能够在不同地区用同样的设备可以提供相同的服务，支持多协议多标准的宽带接收机是最好的解决方案。本文详细介绍了应用于数字电视调谐器的宽带可变增益低噪声放大器的设计。首先，根据现存的数字电视广播标准及多标准多频带调谐器的指标要求，确定了宽带可变增益低噪声放大器的性能指标，接着介绍了低噪声放大器的基本概念和最常见的低噪声放大器结构，分析并总结各种结构的核心思想和优缺点。其次，着重分析了有源负反馈结构的低噪声放大器，包括其电压放大倍数、输入反射损耗、噪声系数、输入三阶交调点和稳定性等内容。然后，以有源负反馈结构为可变增益低噪声放大器的高增益放大模块，并采用恒定跨导偏置技术，结合无源电阻分压衰减器构建出完整的 CMOS 宽带可变增益低噪声放大器；同时，分析低噪声放大器的增益及增益台阶的稳定、噪声系数和输入三阶交调点等设计指标。最后，完成整体可变增益低噪声放大器的版图设计和后仿真。仿真结果表明，在 VHF(50~250 MHz)和 UHF(470~860 MHz)频段，最高增益可分别达到 22 dB 和 20 dB；最高增益模式下，噪声系数可分别低至 1.16 dB 和 1.41 dB；输入三阶交调点分别为+0.5 dBm 和+1 dBm；输入反射损耗保持在−11 dB 和−8 dB 以下。电源电压为 1.8 V 时，在 VHF 和 UHF 工作频段下电路消耗的电流都小于 8 mA。关键词：数字电视调谐器、宽带可变增益低噪声放大器、电阻衰减器、噪声系数、线性度中图分类号：TN432

Abstract During the last few decades,many of the developed countries have moved from analog terrestrial broadcasting to digital broadcasting,including the United States,the Republic of Korea,Western Europe,and Japan. Deployment of DTV(Digital TV)systems has also begun in South America, China and the rest of North America.Many countries have developed their own standards,and video reception with hand-held mobile devices has drawn more and more attention.A multi-standard,multi-band wideband receiver has been proved to be one of the most efficient candidates to enable the same service in different areas. In this thesis,a wideband variable gain low noise amplifier(VGLNA)in a DTV tuner is designed and discussed in great detail. First of all,requirements of the wideband VGLNA are given based on a variety of DTV broadcast standards and the given specification of a multi-standard multi-band tuner.Then,basic concepts and core ideas of LNAs are discussed in detail. Secondly,a wideband LNA based on an active feedback technique is presented in great detail,including the voltage gain,the input return loss,NF, IIPa and stability etc. Thirdly,the active feedback LNA serves as the core amplifier of VGLNA, where constant-Gm biasing technique is used.Resistive attenuator is added to compose a complete CMOS LNA with a specified range of gain control; meanwhile,a great attention is paid in the analysis and discussion of the gain range,gain step,NF and /IPa etc. Finally,the layout of the VGLNA is presented and simulated results are given.According to the post simulation results,the VGLNA has a voltage gain of 22 dB and 20 dB respectively in VHF(50~250 MHz)and UHF(470~860 MHz)bands.At the maximum gain,NF can be as low as 1.16 dB and 1.41 dB, //P3 is +0.5 dBm and +1 dBm,S11 keeps lower than-10 dB and-8 dB,in VHF and UHF bands,respectively.The supply voltage is 1.8 V,and the current consumption is lower than 8 mA in both VHF and UHF bands. Keywords:TV-Tuner,Wideband Variable Gain Low Noise Amplifier, Resistive Attenuator,Noise Figure,Linearity Classification Code:TN432 3

3 Abstract During the last few decades, many of the developed countries have moved from analog terrestrial broadcasting to digital broadcasting, including the United States, the Republic of Korea, Western Europe, and Japan. Deployment of DTV (Digital TV) systems has also begun in South America, China and the rest of North America. Many countries have developed their own standards, and video reception with hand-held mobile devices has drawn more and more attention. A multi-standard, multi-band wideband receiver has been proved to be one of the most efficient candidates to enable the same service in different areas. In this thesis, a wideband variable gain low noise amplifier(VGLNA) in a DTV tuner is designed and discussed in great detail. First of all, requirements of the wideband VGLNA are given based on a variety of DTV broadcast standards and the given specification of a multi-standard multi-band tuner. Then, basic concepts and core ideas of LNAs are discussed in detail. Secondly, a wideband LNA based on an active feedback technique is presented in great detail, including the voltage gain, the input return loss, NF, IIP3 and stability etc. Thirdly, the active feedback LNA serves as the core amplifier of VGLNA, where constant-Gm biasing technique is used. Resistive attenuator is added to compose a complete CMOS LNA with a specified range of gain control; meanwhile, a great attention is paid in the analysis and discussion of the gain range, gain step, NF and IIP3 etc. Finally, the layout of the VGLNA is presented and simulated results are given. According to the post simulation results, the VGLNA has a voltage gain of 22 dB and 20 dB respectively in VHF(50~250 MHz) and UHF(470~860 MHz) bands. At the maximum gain, NF can be as low as 1.16 dB and 1.41 dB, IIP3 is +0.5 dBm and +1 dBm, S11 keeps lower than −10 dB and −8 dB, in VHF and UHF bands, respectively. The supply voltage is 1.8 V, and the current consumption is lower than 8 mA in both VHF and UHF bands. Keywords: TV-Tuner，Wideband Variable Gain Low Noise Amplifier， Resistive Attenuator，Noise Figure, Linearity Classification Code: TN432

第一章概述 MMB(China Multimedia Mobile Broadcasting)标准[6]。上述标准定义的频率范围大多涵盖VHF(50~250MHz)和UHF(470~860MHz)频带。表1-1数字电视调谐器性能指标 DVB-T/H,ATSC-MH,ISDB-Tss, DTV Standards DAB, T-DMB,DTMB, CMMROLIHEY Frequency Range VHF(50~250MHz)/UHF(470~860MHz) RF Input Range -110 dBm~+10 dBm Gain Range -6dB~114dB NF@Max Gain -10 dBm Power Consuption <72 mW VDD=1.8 V Area <4 mm2@0.18-um CMOS 多种标准和协议并存是目前数字移动电视接收领域的客观事实和特点。消费者希望在不同地区用同样的设备可以享受到相同的服务，所以支持多协议多标准的宽带接收机是最好的解决方案之一。单片集成、低功耗、低成本和支持多标准多频带的数字电视调谐器的研究和设计已经得到了广泛的重视7-[13]。多标准和多频带的调谐器要能够处理50~860MHz范围内的信号。为了满足宽带应用，就要解决宽带时出现的谐波混频抑制(Harmonic Mixing Rejection)和镜像抑制(Image Rejection)等问题。传统的上/下双变频结构在功耗和面积上都无法满足移动电视接收的要求3]。在一定功耗和面积要求下，宽带直接变频结构被证明是最合理且最有效的解决方案[14]-[19]，其典型结构框图如图1-1所示2]。不同的标准对调谐器的灵敏度及抗干扰性能有不同的要求，其中DVB-H的测试条件最为严格2]3]。根据测试条件的要求，可以定出满足要求的调谐器的各项性能指标，见表1-1。 1.2宽带可变增益低噪声放大器由于直接变频结构中的混频器往往有较高的噪声，所以必须在混频之前增加低噪声放大器。这样将改善调谐器的噪声性能，满足系统灵敏度的要求。数字电视调谐器中的宽带低噪声放大器的实现方式一般有两种，一种是多个可调谐的窄带低噪声放大器组合实现宽频带的信号接收（图1-2(）)，另一种是宽带低噪声放大器覆盖整个信号频带（图1-2(b)。前者只要比较低的功耗就可以得到较高的增益，较好的噪声系数和中等的线性度，尤其是可以很好的解决低噪声 6

第一章概述 6 MMB(China Multimedia Mobile Broadcasting)标准[6]。上述标准定义的频率范围大多涵盖VHF(50~250 MHz)和UHF(470~860 MHz)频带。表 1-1 数字电视调谐器性能指标 DTV Standards DVB-T/H，ATSC-MH，ISDB-Tss， DAB， T-DMB，DTMB， CMMB(UHF) Frequency Range VHF(50~250 MHz)/UHF(470~860 MHz) RF Input Range -110 dBm~+10 dBm Gain Range -6 dB~114 dB NF @ Max Gain -10 dBm Power Consuption <72 mW @ V DD=1.8 V Area <4 mm2 @ 0.18-μm CMOS 多种标准和协议并存是目前数字移动电视接收领域的客观事实和特点。消费者希望在不同地区用同样的设备可以享受到相同的服务，所以支持多协议多标准的宽带接收机是最好的解决方案之一。单片集成、低功耗、低成本和支持多标准多频带的数字电视调谐器的研究和设计已经得到了广泛的重视[7]-[13]。多标准和多频带的调谐器要能够处理50~860 MHz范围内的信号。为了满足宽带应用，就要解决宽带时出现的谐波混频抑制(Harmonic Mixing Rejection)和镜像抑制(Image Rejection)等问题。传统的上/下双变频结构在功耗和面积上都无法满足移动电视接收的要求[3]。在一定功耗和面积要求下，宽带直接变频结构被证明是最合理且最有效的解决方案[14]-[19]，其典型结构框图如图1-1所示[2]。不同的标准对调谐器的灵敏度及抗干扰性能有不同的要求，其中DVB-H的测试条件最为严格[2][3]。根据测试条件的要求，可以定出满足要求的调谐器的各项性能指标，见表1-1。 1.2 宽带可变增益低噪声放大器由于直接变频结构中的混频器往往有较高的噪声，所以必须在混频之前增加低噪声放大器。这样将改善调谐器的噪声性能，满足系统灵敏度的要求。数字电视调谐器中的宽带低噪声放大器的实现方式一般有两种，一种是多个可调谐的窄带低噪声放大器组合实现宽频带的信号接收(图1-2(a))，另一种是宽带低噪声放大器覆盖整个信号频带(图1-2(b))。前者只要比较低的功耗就可以得到较高的增益，较好的噪声系数和中等的线性度，尤其是可以很好的解决低噪声