Minimising EMI through PCB Design and Material Selection - Agenda

Course Summary

1. Material properties of PCBs, highlighting the important parameters for high speed circuits (including relative cost and fabrication), and comparing these properties in a wide variety of available laminate materials.
2. Application of the principles of high speed design to EMI on the PCB, demonstrating the critical roles played by the PCB structure, components, IC packaging, interconnection and grounding in EMI generation and propagation. This course, in addition to providing practical guidance on EMI control, reinforces good practice based on an understanding of the underlying physical principles.

Uniquely, the course is liberally illustrated with examples and "what if" scenarios showing the effects of varying different parameters, enabling participants to develop an understanding of their relative importance and magnitude. Helpful guidelines on assessing and implementing best practice are included.

• Digital design engineers who either have no experience of the background and methods required for high-speed PCB design, or who have some experience but would benefit from a more complete and in-depth knowledge of the topics presented.
• PCB designers working on digital boards where high-speed design rules are required.

Workshop Agenda

• PCB material properties
• PCB material requirements for high-speed circuits
• Key laminate and cladding parameters
• FR-4 - the industry standard
• Epoxy fibreglass material
• PTFE/ceramic materials
• Beyond FR-4 - routes to higher performance
• Multilayer process
• Outline of multilayer process steps (including buried capacitance and microvias)
• EMC control
• EMC concerns for designers
• Why EMI has become a major issue
• EMI mechanisms
• The five factors in EMI analysis
• EMI from digital systems – what can we control?
• Worldwide regulatory requirements
• Principles of EMI generation
• Electromagnetic wave propagation
• Near field and far field - the radiated signal
• Generation of RF fields on a PCB
• Differential mode and common mode current
• Differential mode and common mode radiation
• PCB structure
• Layer stacking in the PCB
• The 20-H rule
• Image planes
• RF current loops due to power and ground
• Grounding concepts and methods
• Electrically long tracks (l/20 rule)
• System partitioning – multipoint grounding
• Ground plane integrity
• Via properties
• Components and EMC
• IC packaging
• Ground bounce
• Lead capacitance
• EMC techniques for large heatsinks
• Power line filtering
• EMC control at component level
• Connectivity and interconnection
• Split planes
• Power plane filtering
• PCB with split planes – isolation and bridging
• Localised ground plane
• System interconnections – connectors, cables and backplanes
  
• RF coupling – PCB to PCB and PCB to cardcage
• Indirect multipoint grounding
• Backplane connectors and signal routing
• Review and summary
  • Other EMC factors – transmission lines, crosstalk, electrostatic discharge
    
  • Review of EMI control principles