Signal Integrity Study Of Differential Transmission Lines Based On Low Voltage Differential Signal

With the increment of clock frequency and the shorter rising time of signal,the using of traditional single transmission line is limited.Therefore,differential interconnection is always used in the transmission of high speed signal.As one of the high speed transmission line,LVDS is widly used in many modern communication devices.With the development of high speed,high integrity,low voltage and low power in hardware system.High speed differential interconnection always meets the big challenges,such as crosstalk,reflection and power noise.Therefore,the signal integrity study about this has important actual meaning.The general research idea of this paper is firstly modeling and simulation of passive interconnection and active driver.And then this paper designed LVDS routing of a mobile phone circuit board of the internship company and done simulation and analysis of signal and power integrity.For the passive interconnection,this paper mainly studied differential stripline and gnd vias.The transmission line model was established using ADS software,and the via model was built using HFSS software.The paper analysed the length,spacing,couping characteristic of differential stripline and mainly studied the number and layout of gnd vias by modeling and simulation ways.Based on these studies,making a conclusion about differential line and gaving a guidance for LVDS's design.For the active driver model,this paper firstly analysed the simulation result of Spice and generated the IBIS model based on Spice model.And then comparing the simulation results of Spice and IBIS to ensure the accuracy of IBIS.At the last,this paper designed the LVDS routing of a PCB.Considering the non-ideal of the power supply,the paper came up with the co-simulation way of signal and power.And based on this way,this paper done SI/PI co-simulation and analysis for this PCB.The simulation and test results of the paper show that by adding the decoupling capacitor to optimize power network and to reduce the power supply noise and SI problem.The final result shows that the design meets the requirements.The study about differential interconnection of LVDS in this paper can provide a reference for design of other differential routing of system(such as USB,MIPI and so on).And the co-simulation and analysis way of signal and power came up in this paper can be used in any high-speed interconnection.The research results of this paper have a strong engineering practicality and reference value for study of signal and power integrity of actual high-speed serial interconnection.