Research And Testing Of Noise Suppression In High Speed Circuits

Since the birth of Moore's Law,the modern electronic systems are faster,denser,and lower power consumption,with the IC process continues to progress,the channel length is shorter and shorter,resulting in digital signal rise time and fall time becomes smaller and smaller,So that the system's noise environment is getting worse,if noise occurs between the signals can cause signal integrity problems(SI),If it appears in the power supply will bring power integrity issues(PI),If covered with the entire system will cause electromagnetic compatibility problems(EMC),which cause serious impact on the stability of high-speed circuit system.How to solve the problem of signal integrity,power integrity,electromagnetic compatibility issues can become a key factor for High-Speed Circuit Design.In this paper,based on the theory of transmission line effect in high-speed circuit system,Aiming at the SI problem of the modern high-speed circuit system,the reflection and crosstalk problem and the power supply noise problem of the board-level system are analyzed.And combining with board-level simulation software Hyperlynx to verify the methods of Suppressing Reflecting Noise.Aiming at the problem of power noise,this paper introduces a design method of reducing supply noise-target impedance method.In addition,this paper analyzes the causes of electromagnetic interference(EMI)in high-speed circuit system from the angle of electromagnetic compatibility,and gives the measures to suppress electromagnetic interference.Aimed at the signal integrity of the differential pair commonly used in high-speed circuit systems,this paper makes a detailed and in-depth study,the generation mechanism of the far-end crosstalk of the differential pair and the correlation change rule are obtained,And four methods to reduce the far-end crosstalk of the differential pair are proposed,and verified by Hyperlynx.Finally,a switching power supply electromagnetic interference(EMI)problems were tested and rectification based on GTEM Cell in this paper.Not only found the cause of EMI,But also improved the switch the power supply EMI problem through the grounding,filtering,shielding and other rectification methods,finally,the test and rectification results based on GTEM cell are verified by 3m anechoic chamber.