Research On Signal Integrity Of High Speed Serial Interconnect Structure Based On LVDS

With the rapid development of electronic technology,high speed serial interconnection is more and more used in the design of high speed circuits.Low Voltage Differential Signaling(LVDS)technology is widely used in high speed serial interconnects as a differential signal technology for high speed data transmission systems.With the great improvement of clock frequency and signal rate,the high speed serial interconnection structure based on LVDS also faces many signal integrity problems.Therefore,it is important to research the signal integrity of the high speed serial interconnection structure based on LVDS.This paper firstly introduces and analyzes the related theoretical knowledge and key technologies involved in high speed serial interconnect,LVDS technology and signal integrity.On the basis of theoretical research,the transmission line structure and the via structure in high speed serial interconnection are researched in depth.For the transmission line structure,the influence of line length,bend,spacing and return path of LVDS transmission line structure on signal integrity is researched.The above factors are modeled and simulated by using Ansoft HFSS and Ansoft Designer.The influence of the above factors on the signal integrity of the transmission line structure is analyzed by using the variation of mixed-mode S parameters,the continuity of impedance in time domain and the distribution of electric field in simulation results.On this basis,the design optimization scheme of the transmission line structure in high speed serial interconnection is proposed.For the via structure,the equivalent physical model and equivalent circuit model are established for the via structure firstly,and the twin-rod transmission line model is used to analyze and predict the performance of the via.Through this model,the factors affecting the performance of the via are determined,including non-functional structure,center distance of vias,diameter of anti-pad and number of return vias.Then,the above factors are modeled and simulated by using Ansoft HFSS respectively.The influence of the above factors on the signal integrity of the via structure is analyzed by using the variation of mixed-mode S parameters,the continuity of impedance in time domain and the distribution of electric field in simulation results.On this basis,the design optimization scheme of the via structure in high speed serial interconnection is proposed.Based on the research results of signal integrity of high speed serial interconnection structure based on LVDS,this paper proposes a set of relatively complete optimization schemes for its design in high speed circuit,which has high practicability and reference value for the design of high speed serial interconnection structure in practice.