高速数字PCB互连设计信号完整性研究
摘要
随着数字系统时钟频率越来越高,信号跳变时间越来越短,高速数字PCB的互连设计对整个系统电气性能的影响也越来越大。高速系统中,高速信号经过互连线时会产生一系列的信号完整性(Signal Integrity,简称SI)问题。因此,如何处理由高速互连引起SI问题,已成为高速数字系统设计成功与否的关键问题之一。
本文主要研究由高速无源互连单元所引起的延时、反射、串扰、不连续性等SI问题。首先分析了反射和串扰发生的机理,并给出了通过端接技术减小反射的仿真波形和通过改变传输线参数对串扰影响的仿真波形,得出了一些减小串扰的措施。然后,分析了差分阻抗控制及差分对抗串扰能力。通过“场”“路”结合的方法对差分互连的传输特性和远端串扰进行了建模仿真分析,并推导出奇模、偶模传播速度存在差异,导致差分微带结构引入额外噪声。最后,对高速互连设计中的单端和差分互连不连续性问题如:过孔、拐角和回流不连续进行SI分析和建模仿真,通过对S参数曲线的分析得出:过孔的传输特性与过孔孔径、焊盘和反焊盘的直径大小有关;单端拐角中的45°外斜切结构具有更好的传输性能,差分拐角的长度不匹配会引入差分噪声,差分噪声的大小与信号上升时间有关;地平面开槽造成回路电感增加,引入不连续,设计中应避免参考平面的开槽。总之,由仿真和分析结果可以得出一些减小SI问题的结论,由此制定相关的布局、布线规则来约束PCB设计,可以达到良好的设计效果,缩短研发周期,也进一步证明了对高速互连进行信号完整性分析的重要意义。
As the digital system's clock frequency is growing higher and the signal's switch time is getting shorter,and the impact of high-speed digital PCB interconnect design on the whole system's electrical characteristic is growing greater.In high-speed system,the interconnect among the high-speed signals will cause a series of signal integrity issues.Therefore,how to deal with the signal integrity issues caused by high-speed signal interconnects has become the key of a high-speed digital system design to success.
This dissertation mainly studies Delay,Reflection,Crosstalk,discontinuity of microstrip, and other signal integrity issues caused by high-speed interconnects.This dissertation first analysed the reasons of reflection and crosstalk,and also shows the waveforms of reducing reflection by adding terminators and the waveforms of the crosstalk influenced by changing the parameters of transmission lines.And we got some measures to reduce crosstalk.Then, we focus on the differential line impedance control and anti-crosstalk ability of differential pairs.Through.the "field"&"Circuit" method,the difference interconnect transmission characteristic and the far-end crosstalk were simulated and analysed.Because the odd-mode and even-mode's propagation velocity existed difference,the difference microstrip structure in(?)uced extra noise.Finally,we do SI analysis and simulation to the discontinuity of the high speed interconnect such as:via,corner and slot.Through the analysis of S-parameters, we got these:a via transmission characteristic relates with the via,pad and anti-pad's diameter;The 45°outside bevelling structure has better transmission characteristic.The mismatch of differential comer length introduces difference noise,which relates with the rise time;The slot in ground plane causes the return route inductance to increase,introduces discontinuity,it should be avoided in the design.In short,we could draw some conclusions which can reduce SI issues through simulation and analysis.According to these,we can make layout,routing rules to restrain PCB design,so the design can achieve good performance,shorten the development cycle of hardware.And it also proved the importance to make SI analysis to high-speed interconnect.
本文主要研究由高速无源互连单元所引起的延时、反射、串扰、不连续性等SI问题。首先分析了反射和串扰发生的机理,并给出了通过端接技术减小反射的仿真波形和通过改变传输线参数对串扰影响的仿真波形,得出了一些减小串扰的措施。然后,分析了差分阻抗控制及差分对抗串扰能力。通过“场”“路”结合的方法对差分互连的传输特性和远端串扰进行了建模仿真分析,并推导出奇模、偶模传播速度存在差异,导致差分微带结构引入额外噪声。最后,对高速互连设计中的单端和差分互连不连续性问题如:过孔、拐角和回流不连续进行SI分析和建模仿真,通过对S参数曲线的分析得出:过孔的传输特性与过孔孔径、焊盘和反焊盘的直径大小有关;单端拐角中的45°外斜切结构具有更好的传输性能,差分拐角的长度不匹配会引入差分噪声,差分噪声的大小与信号上升时间有关;地平面开槽造成回路电感增加,引入不连续,设计中应避免参考平面的开槽。总之,由仿真和分析结果可以得出一些减小SI问题的结论,由此制定相关的布局、布线规则来约束PCB设计,可以达到良好的设计效果,缩短研发周期,也进一步证明了对高速互连进行信号完整性分析的重要意义。
As the digital system's clock frequency is growing higher and the signal's switch time is getting shorter,and the impact of high-speed digital PCB interconnect design on the whole system's electrical characteristic is growing greater.In high-speed system,the interconnect among the high-speed signals will cause a series of signal integrity issues.Therefore,how to deal with the signal integrity issues caused by high-speed signal interconnects has become the key of a high-speed digital system design to success.
This dissertation mainly studies Delay,Reflection,Crosstalk,discontinuity of microstrip, and other signal integrity issues caused by high-speed interconnects.This dissertation first analysed the reasons of reflection and crosstalk,and also shows the waveforms of reducing reflection by adding terminators and the waveforms of the crosstalk influenced by changing the parameters of transmission lines.And we got some measures to reduce crosstalk.Then, we focus on the differential line impedance control and anti-crosstalk ability of differential pairs.Through.the "field"&"Circuit" method,the difference interconnect transmission characteristic and the far-end crosstalk were simulated and analysed.Because the odd-mode and even-mode's propagation velocity existed difference,the difference microstrip structure in(?)uced extra noise.Finally,we do SI analysis and simulation to the discontinuity of the high speed interconnect such as:via,corner and slot.Through the analysis of S-parameters, we got these:a via transmission characteristic relates with the via,pad and anti-pad's diameter;The 45°outside bevelling structure has better transmission characteristic.The mismatch of differential comer length introduces difference noise,which relates with the rise time;The slot in ground plane causes the return route inductance to increase,introduces discontinuity,it should be avoided in the design.In short,we could draw some conclusions which can reduce SI issues through simulation and analysis.According to these,we can make layout,routing rules to restrain PCB design,so the design can achieve good performance,shorten the development cycle of hardware.And it also proved the importance to make SI analysis to high-speed interconnect.
引文
[1]Stephen H.Hall,Garrett W.Hall,James A.McCall.High-Speed Digital System Design[M].2000,1-6
[2]Paolo Ciampolini,Paolo Mezzanotte,et al.Accurate and Efficient Circuit Simulation with Lumped Element FDTD Technique[J].IEEE Transactions on Microwave Theory and Techniques,1996,44(12):2207-2215
[3]Alain Bossavit,Lauri Kettunen.Yee-Like Schemes on Staggered Cellular Grids:A synthesis Between FIT and FEM Approaches[J].IEEE Transcations on Magnetics,2000,36(4):861-867
[4]Jong-Gwan Yook,Nihad I.Dib,Linda P.B.Katehi.Characterization of High Frequency Interconnects Using Finite Difference Time Domain and Finite Element Methods[J].IEEE Transactions on Microwave Theory and Techniques,1994,42(9):1727-1736
[5]Yun Ji,Todd H.Hubing.On the Interior Resonance Problem When Applying a Hybrid FEM/MoM Approach to Model Printed Circuit Boards[J].IEEE Transactions on Electromagnetic Compatibili ty,2002,44(2):318-323
[6]王长清,祝西里.电磁场计算中的时域有限差分法[M],北京:北京大学出版社,1994
[7]高本庆.时域有限差分法[M],北京:国防工业出版社,1995
[8]葛德彪,闫玉波.电磁波时域有限差分方法[M],西安:西安电子科技大学出版社,2002.
[9]张海风.Hyperlynx仿真与PCB设计[M].机械工业出版社,2005
[10]基于信号完整性分析的高速数字PCB的设计方法,http://www.pcbbbs.com
[11]西安电子科技大学模式识别与控制研究所.IBIS模型简介,http://www.pcbbbs.com
[12]周洪亮,刘志远.基于IBIS模型的仿真在电路设计中的应用[J].安全与电磁兼容,2006,3:76-78
[13]HP corporation.S-Parameter Techniques.http://www.hp.com/go/tmapnottes.
[14]张华,洪伟,崔铁军.混合模S参数理论在信号完整性分析中的应用[J].2003年全国微波毫米波会议论文集:1000-1003
[15]毕明,陈光福,谢永乐.高速数字电路中信号反射的分析及解决方案[J].中国测试技术,2007,33(1):99-101
[16]Eric Bogatin著,李玉山,李丽平译.信号完整性分析[M].电子工业出版社,2005
[17]康壮.高速数字电路中的终端匹配技术[J].声学与电子工程,2004,73:13-639
[18]李朝辉.高速数字电路的设计与仿真[D].燕山大学,2006
[19]韩海涛.高速数字PCB板互连噪声建模与仿真[D].电子科技大学,2003
[20]后盾.信号完整性分析及其在高速数字电路设计中的应用[D].浙江大学,2004
[21]汪学刚.信号完整性分析及其在高速PCB设计中的应用[D].电子科技大学,2006
[22]夏凡.高速数字电路中的信号完整性设计[D].南京理工大学,2006
[23]杨洪军.信号完整性分析及其在高速PCB设计中的应用[D].电子科技大学,2006
[24]Douglas Brooks著,刘雷波,赵岩译.信号完整性问题和印制电路板设计[M].机械工业出版社,2005
[25]魏丽丽.LVDS技术及其在高速PCB设计中的应用[J].电子测量,2007,3:78-80
[26]王胜,王新宇.LVDS技术及其在高速系统中的应用[J].第十三届全国遥感遥测技术年会论文,284-289
[27]郝为强.差分阻抗控制与匹配的Hyperlynx仿真分析[J].印制电路信息,2006,11:40-43
[28]徐孟祥,张尔扬.LVDS与高速PCB设计[J].电子工程师,2005,31(5):38-40
[29]Ansoft Corporation.Ansoff High Frequency Structure Simulator v10 User's Guide.2005
[30]李磊,谢拥军.Ansoft高级培训班教材.西安电子科技大学Ansoft培训中心,2007
[31]谢拥军,王鹏.Ansoft Hfss基础及应用[M].西安电子科技大学出版社,2007
[32]Howard Johnson,Martin Graham.High-Speed Digital Design[M].2007
[33]Stephen H.Hall,Garrett W.Hall,James A.Call.High-Speed Digital System Design[M].2000
[34]张华.高速互连系统的信号完整性分析[D].东南大学,2005
[35]魏丽丽,刘浩.高速PCB过孔设计[J].电子质量,2007,9:76-79
[36]袁子建,吴志敏,高举.高速PCB的过孔设计[J].电子工艺技术,2002,23(4):158-160
[37]贾硕.印制电路板的过孔.印制电路[J],2005,6:13-14
[38]Montrose M.Time and frequency domain analysis for right angle comers on printed circuit board traces[J].Proceedings of IEEE International Symposium on Electromagnetic Compatibility.Piscataway,USA:IEEE,1998:551-556.
[39]Kergonou G,Drissi M,Zak T,et al.Frequency dependence in high speed interconnection[J].Proceedings of IEEE International Sym po sium on Electromagnetic Compatibility.Piscataway,USA.IEEE,2001:632-634.
[40]Silvester P,Benedek P.Micro-strip discontinuity capacitances for right-angle bend,T junctions,and crossings[J],tEEE Transactions on Microwave Theory and Techniques,1993,21(5):341-346
[41]Douvilie J P,James D S.Experiment study of symmetric micro-strip bends and their compensation[J].IEEE Transactions on Microwave Theory and Techniques,1998,26(3):175-182.
[42]路宏敏,安晋元,赵益民,朱满座.印制线拐角的频域分析[J].西安交通大学学报,2007,41(12):1451-1454
[43]施华娟,孟繁义,吴群.高速PCB回流不连续性仿真研究[J].2003年全国微波毫米波会议论文集,107-110
[44]Ammar B,Kouki.Analysis of a Thin Slot Discontinuity in theReference Plane of a Microstrip Structure[J].IEEE Transactions on Microwave Theory and Techniques,1993,41(8):1356-1361.
[45]Mikio Tsuji,Hiroshi Shigesawa.New Interesting Leakage Behavior on Microstrip Lines with a Slot on a Ground Plane[J].IEEE Transactions on Microwave Theory and Techniques,2003 IEEE MTT-S Digest:673-676
[46]A.K.Bhattacharyya,Y.M.M.Antar,A.Ittipiboon.Full wave analysis for the equivalent circuit of an inclined slot on a microstrip ground pl.ane[J].IEEE Transactions on Microwave Theory and Techniques,1992,139(3):245-250
[47]Yakushi KO,Kenji Ito,Junichi Kudo.Electromagnetic Radiation Properties of a Printed Circuit Board with a Slot in the Ground Plane[J].IEEE Int,.Symp.EMC,Denver,1998,8:576-579
[48]经纬,闰美云.弯曲不连续的差分传输线[J].电子质量,2007,6:66-69
[49]经纬.不同差分传输线线形对信号完整性的影响.印制电路信息[J],2007,9:37-41
[50]Guang-Hwa Shiue,Wei-De Guo,Li-Shang Liu,and Ruey-Beei Wu.Circuit Modeling and Noise Reduction for Bent Differentid Transmission Lines[J].IEEE Transactions on Microwave Theory and Techniques,2004,4(10):143-146
[51]Guang-Hwa Shiue,Wei-Da Guo,Chien-Min Lin.Noise Reduction Using Compensation Capacitance for Bend Discontinuities of Differential Transmission Lines[J].IEEE Transactions on advanced packaging,2006,29(3):560-569
[52]Douglas Brooks.Differential Signals Rules to Live By.http://www.ultracad.com
[53]赵忠文,曾峦,熊伟.LVDS技术分析和应用设计[J].指挥技术学院学报,2001,12(6):90-93
[54]张健,吴晓冰.LVDS技术原理和设计简介[J].集成电路应用,2000,10:60-62
[2]Paolo Ciampolini,Paolo Mezzanotte,et al.Accurate and Efficient Circuit Simulation with Lumped Element FDTD Technique[J].IEEE Transactions on Microwave Theory and Techniques,1996,44(12):2207-2215
[3]Alain Bossavit,Lauri Kettunen.Yee-Like Schemes on Staggered Cellular Grids:A synthesis Between FIT and FEM Approaches[J].IEEE Transcations on Magnetics,2000,36(4):861-867
[4]Jong-Gwan Yook,Nihad I.Dib,Linda P.B.Katehi.Characterization of High Frequency Interconnects Using Finite Difference Time Domain and Finite Element Methods[J].IEEE Transactions on Microwave Theory and Techniques,1994,42(9):1727-1736
[5]Yun Ji,Todd H.Hubing.On the Interior Resonance Problem When Applying a Hybrid FEM/MoM Approach to Model Printed Circuit Boards[J].IEEE Transactions on Electromagnetic Compatibili ty,2002,44(2):318-323
[6]王长清,祝西里.电磁场计算中的时域有限差分法[M],北京:北京大学出版社,1994
[7]高本庆.时域有限差分法[M],北京:国防工业出版社,1995
[8]葛德彪,闫玉波.电磁波时域有限差分方法[M],西安:西安电子科技大学出版社,2002.
[9]张海风.Hyperlynx仿真与PCB设计[M].机械工业出版社,2005
[10]基于信号完整性分析的高速数字PCB的设计方法,http://www.pcbbbs.com
[11]西安电子科技大学模式识别与控制研究所.IBIS模型简介,http://www.pcbbbs.com
[12]周洪亮,刘志远.基于IBIS模型的仿真在电路设计中的应用[J].安全与电磁兼容,2006,3:76-78
[13]HP corporation.S-Parameter Techniques.http://www.hp.com/go/tmapnottes.
[14]张华,洪伟,崔铁军.混合模S参数理论在信号完整性分析中的应用[J].2003年全国微波毫米波会议论文集:1000-1003
[15]毕明,陈光福,谢永乐.高速数字电路中信号反射的分析及解决方案[J].中国测试技术,2007,33(1):99-101
[16]Eric Bogatin著,李玉山,李丽平译.信号完整性分析[M].电子工业出版社,2005
[17]康壮.高速数字电路中的终端匹配技术[J].声学与电子工程,2004,73:13-639
[18]李朝辉.高速数字电路的设计与仿真[D].燕山大学,2006
[19]韩海涛.高速数字PCB板互连噪声建模与仿真[D].电子科技大学,2003
[20]后盾.信号完整性分析及其在高速数字电路设计中的应用[D].浙江大学,2004
[21]汪学刚.信号完整性分析及其在高速PCB设计中的应用[D].电子科技大学,2006
[22]夏凡.高速数字电路中的信号完整性设计[D].南京理工大学,2006
[23]杨洪军.信号完整性分析及其在高速PCB设计中的应用[D].电子科技大学,2006
[24]Douglas Brooks著,刘雷波,赵岩译.信号完整性问题和印制电路板设计[M].机械工业出版社,2005
[25]魏丽丽.LVDS技术及其在高速PCB设计中的应用[J].电子测量,2007,3:78-80
[26]王胜,王新宇.LVDS技术及其在高速系统中的应用[J].第十三届全国遥感遥测技术年会论文,284-289
[27]郝为强.差分阻抗控制与匹配的Hyperlynx仿真分析[J].印制电路信息,2006,11:40-43
[28]徐孟祥,张尔扬.LVDS与高速PCB设计[J].电子工程师,2005,31(5):38-40
[29]Ansoft Corporation.Ansoff High Frequency Structure Simulator v10 User's Guide.2005
[30]李磊,谢拥军.Ansoft高级培训班教材.西安电子科技大学Ansoft培训中心,2007
[31]谢拥军,王鹏.Ansoft Hfss基础及应用[M].西安电子科技大学出版社,2007
[32]Howard Johnson,Martin Graham.High-Speed Digital Design[M].2007
[33]Stephen H.Hall,Garrett W.Hall,James A.Call.High-Speed Digital System Design[M].2000
[34]张华.高速互连系统的信号完整性分析[D].东南大学,2005
[35]魏丽丽,刘浩.高速PCB过孔设计[J].电子质量,2007,9:76-79
[36]袁子建,吴志敏,高举.高速PCB的过孔设计[J].电子工艺技术,2002,23(4):158-160
[37]贾硕.印制电路板的过孔.印制电路[J],2005,6:13-14
[38]Montrose M.Time and frequency domain analysis for right angle comers on printed circuit board traces[J].Proceedings of IEEE International Symposium on Electromagnetic Compatibility.Piscataway,USA:IEEE,1998:551-556.
[39]Kergonou G,Drissi M,Zak T,et al.Frequency dependence in high speed interconnection[J].Proceedings of IEEE International Sym po sium on Electromagnetic Compatibility.Piscataway,USA.IEEE,2001:632-634.
[40]Silvester P,Benedek P.Micro-strip discontinuity capacitances for right-angle bend,T junctions,and crossings[J],tEEE Transactions on Microwave Theory and Techniques,1993,21(5):341-346
[41]Douvilie J P,James D S.Experiment study of symmetric micro-strip bends and their compensation[J].IEEE Transactions on Microwave Theory and Techniques,1998,26(3):175-182.
[42]路宏敏,安晋元,赵益民,朱满座.印制线拐角的频域分析[J].西安交通大学学报,2007,41(12):1451-1454
[43]施华娟,孟繁义,吴群.高速PCB回流不连续性仿真研究[J].2003年全国微波毫米波会议论文集,107-110
[44]Ammar B,Kouki.Analysis of a Thin Slot Discontinuity in theReference Plane of a Microstrip Structure[J].IEEE Transactions on Microwave Theory and Techniques,1993,41(8):1356-1361.
[45]Mikio Tsuji,Hiroshi Shigesawa.New Interesting Leakage Behavior on Microstrip Lines with a Slot on a Ground Plane[J].IEEE Transactions on Microwave Theory and Techniques,2003 IEEE MTT-S Digest:673-676
[46]A.K.Bhattacharyya,Y.M.M.Antar,A.Ittipiboon.Full wave analysis for the equivalent circuit of an inclined slot on a microstrip ground pl.ane[J].IEEE Transactions on Microwave Theory and Techniques,1992,139(3):245-250
[47]Yakushi KO,Kenji Ito,Junichi Kudo.Electromagnetic Radiation Properties of a Printed Circuit Board with a Slot in the Ground Plane[J].IEEE Int,.Symp.EMC,Denver,1998,8:576-579
[48]经纬,闰美云.弯曲不连续的差分传输线[J].电子质量,2007,6:66-69
[49]经纬.不同差分传输线线形对信号完整性的影响.印制电路信息[J],2007,9:37-41
[50]Guang-Hwa Shiue,Wei-De Guo,Li-Shang Liu,and Ruey-Beei Wu.Circuit Modeling and Noise Reduction for Bent Differentid Transmission Lines[J].IEEE Transactions on Microwave Theory and Techniques,2004,4(10):143-146
[51]Guang-Hwa Shiue,Wei-Da Guo,Chien-Min Lin.Noise Reduction Using Compensation Capacitance for Bend Discontinuities of Differential Transmission Lines[J].IEEE Transactions on advanced packaging,2006,29(3):560-569
[52]Douglas Brooks.Differential Signals Rules to Live By.http://www.ultracad.com
[53]赵忠文,曾峦,熊伟.LVDS技术分析和应用设计[J].指挥技术学院学报,2001,12(6):90-93
[54]张健,吴晓冰.LVDS技术原理和设计简介[J].集成电路应用,2000,10:60-62