文档介绍：PCB design Consideration for EMI
AgendaAgenda
n Introduction
n Stackup
n 20H rule
n Transmission Line
n The Path of Least Inductance
n Example
n Conclusion
IntroductionIntroduction
Method for EMI improve
n For Plane
n Stackup
n Power Plane Fringing and 20H relation
n Transmission Line
n Path of least Inductance
StackupStackup 44 LayersLayers PCBPCB
• Power and Ground Plane distance
ic Flux eliminate
• Microstrip &Stripline
Stackup1 Signal Stackup2 Ground
Ground Signal / Power
Power Signal / Power
Signal Ground
• Far Distance Between Ground & Power Layer • Best EMI Reduction
PCB Thickness is , 62mil— Center prepreg 48mil ,side prepreg 4mil
StackupStackup 66 LayersLayers PCBPCB
Signal Ground
Stackup1 Signal Stackup2 Stackup3
Power Ground Signal
Signal Signal Power
Center prepreg Center prepreg
Signal Power Ground
Ground Ground Signal
Signal Signal Ground
• Bad EMI Reduction,Good Signal Impedance Control
•Signal & Power Layer Near Ground Layer, Difficult To Manufacture(short)
• Best EMI Reduction,Only Two Layers Can Route Trace
PCB Thickness is , 62mil— Center prepreg 33mil ,side prepreg 4mil
2020HH RuleRule
Power Plane
Fringing => RF Emission
20H 70% Flux boundary
Ground Plane 100H 98% Flux boundary
10H 20H 100H H is distance between Power and Ground plane.
Power Plane generate the Fringing effect b