The Research Of Board-Level Signal Integeity, Power Integrity And Electromagnetic Interference

With the continuous increase of the working frequency and integration of the integrated electronic circuit, the design of circuit board layout will be more and more intense, so the influence of the signals will more and more serious. The potential electromagnetic interference problems can be controlled in the PCB design phase, which is advantage to reduce development costs and short the product development time.In this paper, the control methods of the EMI problems of the high speed PCB have been researched by using simulation software, such as SIwave, HFSS and Designer. The main works as fellows:1. In the first, the the key signals of high-speed PCB have been analysised by using link-analysis, which is on the basis of the transmission line theory. The influence for EMI have been dicussed from the impedance matching, the differential transmission line, crosstalk and return path, which are the key factors for SI.2. A simple PCB with four layers has been created in SIwave, which is used to dicussed the relationship between the Power Distribution Network (PDN) and resonance. Then optimizing the simulation process of PI, it can be proved by an actual PCB. At the same time, the influence for far field radiation caused by PI has been discussed.3. The traditional simulation process of the PCB design has been optimized based the relationship between SI, PI and EMC, and put forward a more efficient modern high-speed design process for the high-speed PCB design.4. The the coupled effect between the shielded conductor and the slots has been researched. A simple ideal case model has been set up in the HFSS, which can be used to research the resonance effect for Shielding Effectiveness (SE) of the shielded conductor. Because of the actual case is not completely closed, there will be connectors, cables, or the cooling holes on it. Their location, size and number will impact the SE. In this paper, these factors will be dicussed, and put forward the theoretical guidance to the actual shielded conductor design.5. The actual case model has been imported in the HFSS and import the far field radiation of actual PCB as a radiation source to discuss the SE of case. The actual case has been optimized by the some measures which have been put forward.