Modeling and measurement of simultaneous switching noise coupling through signal via transition

The signal via is a heavily utilized interconnection structure in high-density System-on-Package (SoP) substrates and printed circuit boards (PCBs). Vias facilitate complicated routings in these multilayer structures. Significant simultaneous switching noise (SSN) coupling occurs through the signal via transition when the signal via suffers return current interruption caused by reference plane exchange. The coupled SSN decreases noise and timing margins of digital and analog circuits, resulting in reduction of achievable jitter performance, bit error ratio (BER), and system reliability. We introduce a modeling method to estimate SSN coupling based on a balanced transmission line matrix (TLM) method. The proposed modeling method is successfully verified by a series of time-domain and frequency-domain measurements of several via transition structures. First, it is clearly verified that SSN coupling causes considerable clock waveform distortion, increases jitter and noise, and reduces margins in pseudorandom bit sequence (PRBS) eye patterns. We also note that the major frequency spectrum component of the coupled noise is one of the plane pair resonance frequencies in the PCB power/ground pair. Furthermore, we demonstrate that the amount of SSN noise coupling is strongly dependent not only on the position of the signal via, but also on the layer configuration of the multilayer PCB. Finally, we have successfully proposed and confirmed a design methodology to minimize the SSN coupling based on an optimal via positioning approach.     

基于螺旋谐振环结构的UWB同步开关噪声抑制电源平面

针对目前印制电路板中采用的同步开关噪声抑制方法抑制带宽较窄、全向性较差、电源平面有效使用面积小、结构复杂及对信号质量影响大的问题,提出了一种基于螺旋谐振环结构的超宽带同步开关噪声抑制平面,具有结构简单、阻带宽、抑制方向具有全向性、无需周期性电磁带隙结构的特点。通过研究其等效电路模型,使用三维有限元法( FEM)对所设计的结构提取了S参数,并进行了频域与时域分析与仿真。仿真结果表明：所提出的结构其同步开关噪声抑制深度在-40 dB时,阻带范围为0.13~20 GHz,抑制带宽达到19.87 GHz,有效降低了带隙中心频率;当注入噪声电压为1 V时,可将噪声电压抑制到0.25 mV;对比UC-EBG和Planar EBG结构,在-40 dB抑制深度时,抑制带宽分别提高了16.97 GHz和17.73 GHz。     

Double-Stacked EBG Structure for Wideband Suppression of Simultaneous Switching Noise in LTCC-Based SiP Applications

We propose a novel electromagnetic bandgap (EBG) structure with a significantly extended noise isolation bandwidth, called a double-stacked EBG (DS-EBG) structure, fabricated on a low-temperature co-fired ceramic (LTCC) multilayer substrate. The DS-EBG structure was devised for wideband suppression of simultaneous switching noise (SSN) coupling in system-in-package (SiP) applications. Our design approach was enabled by combining two EBG layers embedded between the power and ground planes. The two EBG layers had different bandgaps from using different cell sizes. Enhanced wideband suppression of the SSN coupling was validated using a 11.4-GHz noise stop bandwidth with 30-dB isolation in time and frequency domain measurements up to 20GHz.     

Analysis of electromagnetic coupling through a thick aperture inmultilayer planar circuits using the extended spectral domain approachand finite difference time-domain method

Electromagnetic coupling plays a very important role in the design and development of integrated antenna arrays and microwave circuits. With the availability of accurate computer-aided design tools, proper characterization and analysis, this coupling phenomenon could be used to simplify the packaging and fabrication process, to reduce manufacturing cost, and also to add flexibility to the design of multilayer structures in many cases. An accurate and efficient spectral domain approach (SDA) is proposed as a means to study the coupling effect through an arbitrary aperture in a thick common ground plane of multilayer planar circuits. In addition, the finite difference time domain (FDTD) method is present as an alternate approach to this type of problem and also is used as a validation tool for the spectral domain method because of its simplicity, generality, and accuracy. The proposed methods are applied to different aperture coupled structures for illustration     

一种基于互补环缝谐振器抑制SSN的新方法

针对高速PCB上抑制同步开关噪声(SSN)的问题,提出了一种将互补环缝谐振器(CSRR)刻蚀在电源平面上,抑制电源/地平面间的电场波动噪声传播的方法。采用基于有限元算法的HFSS软件对该结构进行仿真分析,结果表明:与理想参考平面和电磁带隙结构相比,刻蚀了该CSRR结构的电源分配网络具有较好的宽带全向SSN噪声抑制能力,在抑制深度为-40 dB时,其阻带覆盖从0.26 GHz到超过20 GHz以上的频率范围。     

S-parameter based technique for simultaneous switching noiseanalysis in electronic packages

A method based on S-parameters is developed for the analysis of simultaneous switching noise (SSN) in electronic packages. A two-port Z matrix of the package pin/trace, and the coupling between the pins/traces are modeled by analytical equations. SSN is analyzed as a function of the number of switching drivers and switching time. Frequency domain measurements are performed to demonstrate the accuracy of the model. The modeling methodology is applied to both leaded and area array packages     

Modeling of irregular shaped power distribution planes usingtransmission matrix method

A major problem in power distribution networks is simultaneous switching noise (SSN), which causes several signal integrity issues. To understand the behavior of the power distribution system (PDS) and its contribution to SSN, noise prediction methods are necessary. This paper presents a method for analyzing arbitrary shaped power distribution networks both in the frequency and time domain. Using a two dimensional array of distributed RLCG circuits, the impedance of a power/ground plane pair is computed. For the efficient computation of the power distribution impedances at specific points in the network, a multi-input and multi-output transmission matrix method has been used. To verify the accuracy of this method, the simulation results have been compared with Spice which uses a circuit based approach and an analytical solution based on the cavity modes in the structure. The simulation results have also been compared with measurements for an L-shaped structure. The transmission matrix method has been applied to a split plane and an arbitrary shaped power plane to demonstrate the application of this technique to irregular geometries     

Bandwidth Enhancement for SSN Suppression Using a Spiral‐Shaped Power Island and a Modified EBG Structure for a λ/4 Open Stub

This paper proposes a spiral‐shaped power island structure that can effectively suppress simultaneous switching noise (SSN) when the power plane drives high‐speed integrated circuits in a small area. In addition, a new technique is presented which greatly improves the resonance peaks in a stopband by utilizing λ/4 open stubs on a conventional periodic electromagnetic bandgap (EBG) power plane. Both proposed structures are simulated numerically and experimentally verified using commercially available 3D electromagnetic field simulation software. The results demonstrate that they achieve better SSN suppression performance than conventional periodic EBG structures.     

Design and modeling of high-impedance electromagnetic surfaces for switching noise suppression in power planes

This paper presents a detailed design and modeling approach for power planes with integrated high-impedance electromagnetic surfaces (HIS). These novel power planes, which were introduced recently, have the unique ability of providing effective broadband simultaneous switching noise (SSN) mitigation. Full-wave electromagnetic simulation is used to study the impact of the geometry on the performance of these novel power planes. It is demonstrated that power planes using inductance-enhanced HIS can be designed for broadband mitigation of the SSN from the upper hundred megahertz to the gigahertz frequencies. Physics-based compact models for the unit cell of power planes with integrated HIS are developed and several of them connected in a two-dimensional array to build full models for large and multilayer power planes. The compact model offers fast analysis of power planes. As an example, we show that the full-wave simulation time of a 10/spl times/10 cm power plane with integrated HIS can be dramatically reduced from 24 to 48 h using a commercially available three-dimensional full-wave solver to less than 1 min when using the compact circuit model developed here.     

电磁带隙结构在同步开关噪声抑制中的应用分析

随着数字电路的噪声容限和时序容限不断减小,电源地平面上的同步开关噪声(SSN)成为高速设计的主要瓶颈之一.而现有抑制SSN的方法存在各自的不足,因而提出采用电磁带隙结构(EBG)设计来抑制SSN,软件仿真证明该方法是有效的.基于对多种不同结构EBG的研究,给出了EBG的设计思路和最新发展趋势,为今后的实际应用研究提供一定的参考与指导.     

具有电或磁耦合关系谐振电路的谐振频率

采用本征值理论分析与电路仿真两种独立的方法,定量计算了具有电耦合或磁耦合关系谐振电路的谐振频率随耦合电容或耦合系数大小的变化关系,两种耦合电路的谐振频率表现出不同的变化规律。这种耦合谐振电路的分析为实际电路设计过程中利用耦合类型及耦合强度对谐振频率进行调谐开辟了新的途径,扩展了现有教学中无耦合谐振电路的教学内容。     

X波段低噪声放大器模块

报道了自行设计并研制成功的X波段低噪声放大器(LNA)模块,提出了调整模块增益平坦度的有效方法,即在两级放大器之间设计多个并联谐振回路,使其在带外低频段产生不同的谐振点来衰减低频段的增益,同时拉低带内低频端的增益,再用谐振回路中的串并联电阻调整增益压缩的大小,从而使工作频带内增益平坦.利用这种方法研制的模块最终测试结果为:增益平坦度≤±0.34dB,噪声系数≤1.84dB,增益＞35dB,模块性能完全符合设计要求.     

A Double-Surface Electromagnetic Bandgap Structure With One Surface Embedded in Power Plane for Ultra-Wideband SSN Suppression

In this letter, a double-surface electromagnetic bandgap (EBG) structure with one EBG surface embedded in power plane is proposed for ultra-wideband simultaneous switching noise (SSN) suppression in printed circuit boards. The SSN suppression bandwidth is broadened to wider than 30 GHz with a low start frequency by combining traditional EBG structure and the coplanar EBG structure which is embedded in the power plane. Because the coplanar EBG surface is embedded in the power plane, no additional metal layer is introduced by the double-surface EBG structure. Simulations and measurements are performed to verify the broadband SSN suppression, high performance is observed.     

A simple finite-difference frequency-domain (FDFD) algorithm for analysis of switching noise in printed circuit boards and packages

Simultaneous switching noise (SSN) compromises the integrity of the power distribution structure on multilayer printed circuit boards (PCB). Several methods have been used to investigate SSN. These methods ranged from simple lumped circuit models to full-wave (dynamic) three-dimensional Maxwell equations simulators. In this work, we present an efficient and simple finite-difference frequency-domain (FDFD) based algorithm that can simulate, with high accuracy, the capacity of a PCB board to introduce SSN. The FDFD code developed here also allows for simulation of real-world decoupling capacitors that are typically used to mitigate SSN effects at sub 1 GHz frequencies. Furthermore, the algorithm is capable of including lumped circuit elements having user-specified complex impedance. Numerical results are presented for several test boards and packages, with and without decoupling capacitors. Validation of the FDFD code is demonstrated through comparison with other algorithms and laboratory measurements.     

A Power Plane With Wideband SSN Suppression Using a Multi-Via Electromagnetic Bandgap Structure

In this letter, a power plane with wideband simultaneous switching noise (SSN) suppression using a novel multi-via electromagnetic bandgap (EBG) structure is proposed. The -40dB stopband of the proposed EBG structure is about two to six times wider than the one-via structure, and the relative bandwidth is increased by about two times. It is implemented by only adding some vias between patches and the reference plane without changing any other geometrical parameters from one-via EBG structures. The excellent SSN suppression performance was verified by simulations and measurements     

Improvements in Noise Suppression for I/O Circuits Using Embedded Planar Capacitors

The performance of embedded planar capacitors in noise suppression of input/output (I/O) circuits and improvements in board impedance profile have been investigated in this paper. Simultaneous switching noise (SSN) is a critical issue in today's systems and this paper shows performance improvements by introducing thin planar embedded capacitors in the board stack up. Measurement and modeling results by including the effects of transmission lines and the power ground plane pairs in the board stack up in the gigahertz range quantify the performance of the embedded capacitors.     

Electric and Magnetic Coupling through Small Apertures in Shield Walls of Any Thickness

A method is presented for evaluating the coupling between two identical resonant cavities coupled by a small aperture in a plane common wall of arbitrary thickness. The coupling is related to the frequencies of the symmetric and asymmetric modes of oscillation of the coupled cavity structure, and a variational technique is used to determine those frequencies. The method is applied to circular and rectangular apertures, and it is shown that the coupling is separable into electric and magnetic terms. The results enable theoretical solutions to be obtained for the electric and magnetic polarizabilities of circular and rectangular apertures in walls of zero thickness, and equivalent polarizabilities to be obtained when the wall thickness is nonzero. Curves of numerical values are given for circular and rectangular apertures. With zero wall thickness, the results obtained are the same as those of Bethe for a circular aperture and give good agreement with Cohn's experimental results for rectangular apertures.     

Simultaneous Switching Noise Suppression in Printed Circuit Boards Using a Compact 3-D Cascaded Electromagnetic-Bandgap Structure

In this paper, a deep bandgap behavior analysis of the vertical cascaded electromagnetic-bandgap (EBG) structure is made. It is shown that the vertical cascaded EBG structure can be decomposed into two EBG structures cascaded horizontally, one with the bigger patches and the other with the smaller patches. The design guidelines of the vertical cascaded EBG structure are drawn. Furthermore, the vertical cascade concept is extended to 3-D cascade for wideband simultaneous switching noise (SSN) suppression. The number of rows of patches for noise coupling reduction is investigated. Building SSN isolation walls along a printed circuit board for wideband electromagnetic-interference reduction and along sensitive devices for SSN isolation using a 3-D cascaded EBG structure is proposed. Simulations and measurements are performed to verify the SSN suppression. High performance is observed.     

一种抑制SSN的新型宽带平面电磁带隙结构

随着现代高速数字电路的快速发展,同步开关噪声(SSN)问题变得越来越突出。该文提出了一种适用于高速数字电路中抑制同步开关噪声的新型宽带平面电磁带隙(EBG)结构,并用Ansoft HFSS软件对该电磁带隙结构进行数据仿真分析。仿真结果表明,在抑制深度为-30dB时,其阻带范围为0.2~5.6 GHz,与传统的L-bridge型电磁带隙结构比较,阻带下限截止频率下降了500 MHz,阻带带宽增加了1.4GHz,相对带宽增加了38.1%,且能全向抑制同步开关噪声。     

An analytical model of simultaneous switching noise in CMOS systems

An accurate and analytical model for simultaneous switching noise (SSN) on ground lines in CMOS circuits is presented. This model can compute SSN for the case where only some drivers switch and the others remain quiet, that is, the model considers the loading effects on the quiet drivers. It was confirmed that the proposed model is more accurate than the existing ones through HSPICE simulation using the level 28 model for short-channel MOSFETs. The proposed model can provide useful design guides for CMOS driver circuits