The PCB Signal Integrity Analysis And Application Based STM32

With the development of electronic production,board size is becoming smaller and smaller,more components,the track density and the working frequency is turn to higher and higher,and layer stack is more complicated.So it is harder to ensure the signal transmission from one pin to another without distortion.During the high-speed PCB design,the Placement?Layer Stack? Routing?Terminating and Power Distribution Network may cause the signal integrity issues.So to ensure the reliability and stability of the PCB,it is important to do the signal integrity analysis during the design.It can avoids multiple modifications,and shorten the design cycle.During the high-speed design,the main signal integrity issues include overshoot?undershoot?ringing?crosstalk?power collapse?and Electromagnetic Interference etc.This dissertation is based on the transmission line and Electromagnetic field theory.Analysis and simulations are made based on IBIS models in HyperLynx.Signal integrity methods are applied in the design of STM32H745 project to reduce the overshoot,undershoot,ringing.It is shown that the crosstalk is under 50mv;power ripple is under 3%.The main contents include:1.Analysis based on the transmission line and Electromagnetic field theory.To improve the singnal integrity,the right terminal resisters are selected.Factors affect crosstalks are analyzed.Crosstalk can be reduced through reducing the decoupling length?track clearance?clearance between signals and reference plane?shielding GND?and selecting right terminators with good matching,Choosing the right decoupling capacitor through the target impedance calculation.Doing the best layout to control the ripple of the MCU power.2.Simulations in HyperLynx to verify the analytical solutions.The terminal resister is selected to reduce the overshoot,ringing.Shielding ground is used to reduce the crosstalk.Decoupling capacitors are made to control the power ripple under requirement.3.Application in STM32H745 project.First,I get data from IBIS model,and calculate the pin output resister.And then I get the right values of terminal resisters.Third,HyperLynx is used to verify if the terminal resister can reduce the overshoot,Space between signals and reference plane are designed for low crosstalk.HyperLynx is used to simaulate if the crosstalk can satisty requirement.Decoupling capacitors are desingned to meet the target impedance,and then simulated in HyperLynx to compute impedance under target impedance in the whole working frequency domain.