Application of system-level EM modeling to high-speed digital IC packages and PCBs (original) (raw)
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Proceedings of the 5th Electronics Packaging Technology Conference (EPTC 2003)
This paper presents an analytical model of power/ground noise coupling to signal traces in high-speed multi-layer systems. The coupling model is expressed in terms of transfer impedance which denotes the coupled noise voltage at the signal trace when switching current occurs. This model is then compared with measured data and full-wave simulated data up to 10 GHz to verify the validity of the model. The results calculated by the proposed model shows good correlation with measurent.
IEEE Transactions on Advanced Packaging, 2003
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.
Computation of Switching Noise in Printed Circuit Boards
Simultaneous switching noise (SSN) is a phenomenon with adverse and severe effects when a large number of high speed chip drivers switch simultaneously causing a large amount of current to be injected into the power distribution grid. The effects of SSN are manifested in a variety of transient and permanent system malfunctions including the appearance of undesirable glitches on what should otherwise be quiet signal lines and the flipping of state bits in registers and memories. Current approaches for dealing with SSN are largely ad hoc, relying primarily on the ability of expert designers to postulate worst-case scenarios for the occurrence of SSN-related errors and to analyze these scenarios using pessimistic estimates of packaging parasitics. This paper takes a first step toward evolving a systematic methodology for modeling and analysis of SSN in printed circuit boards (PCB's). The presented methodology adopts a combination of macro-and micro-models which allow for a system level treatment of the problem without losing the necessary detailed descriptions of the power/ground planes, the signal traces and the vertical interconnections through vias or plated holes. This approach has been applied to a variety of PCB structures and has allowed for an effective characterization of switching noise and a comprehensive understanding of its effects on PCB performance.
IEEE Transactions on Electromagnetic Compatibility, 2006
As layout density increases in highly integrated multilayer printed circuit boards (PCBs), the noise that exists in the power distribution network (PDN) is increasingly coupled to the signal traces, and precise modeling to describe the coupling phenomenon becomes necessary. This paper presents a model to describe noise coupling between the power/ground planes and signal traces in multilayer systems. An analytical model for the coupling has been successfully derived, and the coupling mechanism was rigorously analyzed and clarified. Wave equations for a signal trace with power/ground noise were solved by imposing boundary conditions. Measurements in both the frequency and time domains have been conducted to confirm the validity of the proposed model.
56th Electronic Components and Technology Conference 2006, 2006
Multilayered packages and boards, such as high performance server boards, contain thousands of signal lines, which have to be routed on and through several layers with power/ground planes in between. There can be noise coupling not only in the transversal direction through the power/ground planes in such a structure, but also vertically from one plane pair to another through the apertures and via holes. In addition, the continuous increase in power demand along with reduced Vdd values results in significant current requirement for the future chips. Hence, the parasitic effects of the power distribution system become increasingly more critical regarding the signal integrity and electromagnetic interference properties of cost-effective high-performance designs. We present a multilayer finite-difference method (M-FDM), which is capable of characterizing such noise coupling mechanisms. This method allows to consider realistic structures, which would be prohibitive to simulate using full-wave simulators.
An investigation of PCB radiated emissions from simultaneous switching noise
1999 IEEE International Symposium on Electromagnetic Compatability. Symposium Record (Cat. No.99CH36261)
Processors are currently operating with fundamental clock tiequencies that are at or above the resonant frequencies of typical processor boards and modules. Adequately decoupling printed-circuit boards (PCBs) at high frequencies has become an increasingly urgent task in the light of increasing clock frequencies with decreasing rise times. Providing sufficient charge at frequencies near and above 1 GHz is extremely difficult with lumped-element capacitors. To further complicate the issue, modern PCB power buses may be analgous to microstrip-patch antennas. Exciting a power bus at board harmonics may result in significant radiated EM1 from the bus. Much has been done to improve high-frequency decoupling from a signalintegrity perspective. However, the benefit to EMI is somewhat unclear, because the mechanism by which power-bus noise results in radiated EM1 is not well understood. Input impedance of a power bus, transfer impedance across a power bus, and radiated emissions from a PCB are presented herein. The results are discussed to provide characterization of radiated EMI directly from a PCB power bus.
IC models accounting for effects of EM noise
2008 International Symposium on Electromagnetic Compatibility - EMC Europe, 2008
This paper addresses the generation of enhanced models of digital ICs. The proposed models accurately represent the effects of the fluctuations of the device port signals induced by EM disturbances coupling to the system interconnect. The models can be easily estimated from the device port transient responses and can be effectively implemented in any commercial tool as SPICE subcircuits. Model accuracy is assessed by comparing measurements carried out on a test board and simulations. The effects of both continuous wave sinusoidal and pulsed disturbances are discussed.
IEEE Transactions on Electromagnetic Compatibility, 2000
This paper presents a method for fast and comprehensive simulation of signal propagation, power/ground noise, and radiated emissions by combining the merits of the physics-based via model, the modal decomposition technique, the contour integral method (CIM), and the equivalence principle. The physics-based via model combined with the modal decomposition technique is an efficient technique for signal integrity analysis of multilayer PCBs and packages. The CIM can be used to calculate the voltage distribution between arbitrarily shaped power planes. Far-field radiation can be obtained by applying the field equivalence principle. In this paper, we integrate the four techniques to analyze all the three effects in a fast, concurrent, and holistic manner. To the best knowledge of the authors, the four techniques are integrated here for the first time. Various structures are simulated and validated with full-wave simulations up to 20 GHz. It is shown that a reduction in simulation time of more than two orders of magnitude is achieved in comparison to a standard full-wave electromagnetic solver.