Power Integrity Analysis For Power Distribution Networks In High Speed Circuits

Recent years, large integrated circuits move rapidly toward the trends of high speed, high density and low voltage by the Moore's Law. The CMOS process now has reached 32nm node, and will fastly get to 22nm node in the near future. The clock frequency of microprocessor has also exceeded 3GHz. At the same time, the emergence of package level system integration technichs stimulates the progress of multi-chip and multi-technics system integration technich, and accelerates the system integration speed. Under the driven of System on Package (SoP) technich, electronics industy is moving gradually toward the More than Moore's Law, which is a more attracting integration trend. However, the technich evolutions also make the power integrity problems in high speed electronics system more svere than ever. Power integrity mostly focuses on the analysis and design of power distribution networks in high speed circuits. When the transistors switch simultaneously in the chip, the power delivery system has to supply a very large input current, so there will be a large voltage drop in the power delivery networks, which will greatly influence the transitor swith time and cause timing and stability problems. Meanwhile, voltage noises will couple with the signal lines, which may lead to signal integrity problems. Besides, the voltage noise will resonate between the power ground planes, and generate the effect of EMI (Electromagnetic Interference). Power noise is the major EMI noise source in electronic system. As the electronic systems stride toward the high power and low voltage trends, it becomes more and more difficult for the design of power delivery netwoks. Power integrity has become one of the major bottlenecks for high speed circuit design. In this paper, all of the work is about the frequency domain modeling of power distribution networks in high speed system. For the power/ground planes in power distribution network, we try to analyze and expand the existing excellent methods. Based on the existing methods, we analyze the characteristics of power plane structures, and propose a new power/ground plane modeling method, which is more effective and universal. The partial content notes of this thesis are as follows:The third chapter mainly focuses on the the analytic method, including the eigenmode expansion method and the inverted composition method. We combind the inverted composition method with the eigenmode expansion method, and detailly develop the analysis process and relevant formulations of the round and rectangle aperturtes, which make that the eigenmode expansion method can be applied to power/ground planes with apertures. The work expands the application area of the analytic methods in a maximu sense.Based on the analysis of the third chapter, the fourth chapter makes analysis of the intrinsic characteristics of the power distribution networks. We find that there is a common characteristic of the power/ground planes in both the PCB and package structures, which is that the planes have many large integrated domains. Most of the area of these domains is very large and these domains are connected together without any inner apertures. This characteristic of the power/ground plane makes that the power/ground planes can be modeled in a manner different from the discontinued structures and interconnect lines. Based on this characteristic, we propose a new power/ground modeling method. This method combinds both rectangle partitions and triangulation mesh as the mesh patition method, which may use a few large rectangles to cover most area of the planes and use the triangle mesh to deal with the rest small area. The rectangles are modeled with the analytic cavity model, and the trangle mesh is modeled with triangle equivilant lumped circuits. As most of the area is covered by rectangles, the high efficiency of analytic model can be inherited and the simulation time and memory consumption are both dramaticly reduced. Also, the characteristic of the triangle mesh can be preserved, which can deal with irregular structures and won't introduce staircass approximations in the edges. In this article, we not only develop the partition method based on maximum rectangle searching, and also for the infinite summation of cavity model, we get a closed form equation for the truncation number and prove its accuracy through numerical experiments. For the interconnection of rectangles and triangles, we propose a connect model, which is also proved for its accuracy. The new method can also be applied to multilayered irregular power/ground planes, which shows its generability.