A Study On Crosstalk Of High-speed Digital Design

With the development of high-speed and miniaturization digital systems, the design of signal integrity has become an unavoidable problem for designers. Signal integrity is a complex issue, and research in this field is not mature enough, many designers only have to depend on experiences to solve problems. In the design of signal integrity, crosstalk is a recurring problem during the process and often be the causation of system instability. So it raises the level of difficulty in orientation and becomes the problem our designers face always.Crosstalk, which is the coupling of energy from one line to another, will occur whenever the electromagnetic fields from different structures interact. In digital designs the occurrence of crosstalk is very widespread. Crosstalk will occur on the chip, on the PCB board, on the connectors, on the chip package, and on the connector cables. Furthermore, as technology and consumer demands push for physically smaller and faster products, the amount of crosstalk in digital systems is increasing dramatically. Subsequently, crosstalk will introduce significant hurdles into system design, and it is vital that the engineer learn the mechanisms that cause crosstalk and the design methodologies to compensate for it.This paper firstly introduces the transmission line theory, and gives a detailed analysis of the design of high-speed signal integrity problems, including reflection, crosstalk, simultaneous switching noise,test measure. Then gives a theory of crosstalk, and a detailed analysis of mutual inductance,mutual capacitance,crosstalk-induced noise,termination of odd-and even-mode transmission ling pairs. According to the demands, with the application of signal integrity analysis with crosstalk, completed the simulation of high-speed data collection system, made focus on crosstalk analysis of the key part of the DDR as well as utilize Sigxp of EDA, the product of Cadence Co., to give simulation waveforms for the realization of crosstalk simulation of the given circuit models, introduce crosstalk effects, explain their relevance to digital timings, and explore nonideal transmission line effects. Secondly utilizes Sigxp of EDA, the product of Cadence Co., to realize the crosstalk simulation of the given circuit model. And then gives two simulation waveforms: the first one is formed by terminal-joint technology which is used to reduce reflection, and the second one is formed by changing parameters of the transmission line influenced on the crosstalk. Finally, summarizes the measures of solving crosstalk problem. The paper focuses on the example of the use of DDR to analyze several factors caused crosstalk in detail, and gives waveforms according to each instance and some ways to solve the problems of signal integrity in common situation, it would have a positive impact on the comprehension of crosstalk and provide a useful reference for the ones who do research on signal integrity analysis. It also has a significant effect to help the designers to avoid crosstalk problems in the practical work.