Grounding & Shielding plus Circuit Board Layout

This video option consists of the combination of the 15 hour “Grounding & Shielding” course plus the 5 hour “Circuit Board Layout” course.  Only one final exam must be taken for the two combined courses.  A separate description is given below for each course.

Grounding and Shielding of Electronic Systems
(How to Diagnose and Solve Electrical Noise Problems)

A 15-Hour Video Presentation by Dr. Tom Van Doren

Program Description

This course presents an organized introduction to fundamental grounding and shielding principles, clarifies troublesome terminology, and demonstrates many techniques for identifying and fixing electrical noise problems.  The principles will be described as concepts rather than theoretical equations.  The emphasis on concepts will make the course useful for people with a wide range of experiences.  Several interference mechanisms and shielding techniques are demonstrated.

Benefits

This course will help you to:

1. Use a logical procedure to diagnose and solve electrical noise problems;
2. Reduce the time and cost required to meet emission and susceptibility specifications;
3. Determine the optimum grounding technique for safety and low noise;
4. Recognize that all electrical noise problems are caused by four basic coupling mechanisms; and
5. Determine the correct connection for cable shields.

Course Outline and Learning Objectives

•  denotes key topics
√ denotes learning objectives

Session 1: The Path of Least Impedance

  • Identifying the current path
  • Importance of wiring inductance
  • Demonstration – loop area controls inductance
    √Explain why wiring inductance is more important than resistance.
    √Describe how current loop area is related to self inductance.

Session 2: Electrical Noise Coupling Mechanisms

  • Conductive coupling
  • Magnetic-field coupling
  • Electric-field coupling
  • Electromagnetic-wave coupling
    √ Describe the four noise-coupling mechanisms.
    √ List one key indicator for each mechanism.

 Session 3: Noise Coupling Equivalent Circuits

  • Circuit for each coupling mechanism
  • Parameters critical to noise reduction
  • Example problems
    √  Describe two ways to reduce each of the four coupling mechanisms.

 Session 4: Why and How to Ground Electrical Systems

  • What is “electrical ground?”
  • Reasons for grounding
  • Grounding analog and digital circuits
  • Reducing ground-loop noise
    √ Explain the two reasons for grounding.
    √ Explain the difference between a grounding conductor and a return conductor.

Session 5: Signal Grounding Concepts and Examples

  • Grounding each current only once
  • Where to ground a signal
  • Misuse of single-point grounding
    √ Explain why a signal should be grounded to an external metal enclosure.
    √  Describe signal isolation techniques used to avoid ground loops.

Session 6: How to Diagnose Noise Problems

  • Ringing, rounding and reflections
  • Demonstration – measuring noise
  • Influence of circuit impedance
    √  Describe one noise symptom for each coupling mechanisms.
    √  Use the susceptible circuit impedance to identify the most likely coupling mechanisms.

Session 7: Impedance Balancing and Common Mode Rejection

  • Common mode and differential mode
  • What does impedance balance mean?
  • Demonstration – CM to DM conversion
    √  Recognize the importance of impedance balancing as a noise-reduction technique.
    √  Identify causes of circuit imbalance.

Session 8: Filtering Conducted Noise

  • Types of filters
  • Influence of circuit impedance
  • Controlling mutual inductance
  • Use of ferrite beads
    √  Explain when to use series blocking and shunt diverting filter techniques.
    √  Understand the problem with mutual inductance between input and output.

Session 9: Self Shielding – Low Cost Field Containment

  • The concept of self shielding
  • Self-shielding examples
  • Misuse of twisted pair
    √  Explain how self shielding works.
    √  Describe how self shielding can reduce the use of other shielding materials.

Session 10: Electric-Field Shielding

  • Demonstration – am electric-field coupling problem
  • Where to ground the shield on a twisted pair cable
  • Electric-field shielding examples
    √ List several circuit characteristics that help identify electric-field noise coupling.
    √ Explain how often and where to ground the electric-field shield on a cable.

Session 11: Magnetic-Field Shielding

  • Magnetic-field shunting and reflection
  • Demonstration – magnetic-field shielding
  • Problems with high permeability materials
    √ Identify the frequency ranges over which magnetic-field shunting and reflection are effective.
    √ Describe the difficulties with high-permeability shielding materials.

Session 12: Electromagnetic-Wave Shielding

  • Shielding against ESD and RF
  • 360º shield connections
  • Reducing leakage through seams
  • Dampening chassis resonances
    √ Explain why radiation is influenced more by the quality of the shielding connections than by grounding.
    √ Describe how to control radiation leakage through seams and openings in a metal chassis.

Session 13: Selecting the Right Cable

  • Desirable EMC properties of cables
  • Comparing coaxial and twisted-pair cables
  • Cable selection examplesz
    √ Explain how to evaluate cable alternatives given the noise-coupling mechanism and the signal bandwidth.

Session 14: Circuit Board Layout – Part I

  • Controlling trace inductance
  • Avoiding traces crossing gaps in the return plane
  • Connector placement to reduce emissions
  • DC power distribution
  • Sizing and locating decoupling capacitors
    √ Recognize trace layouts that have excessive inductance.
    √ Design more effective DC power-distribution busses.

Session 15: Circuit Board Layout – Part II

  • Component placement
  • Signal and power stack up alternatives
  • Grounding heat sinks
  • High-speed transmission lines
    √ Compare the placement of signals on outer layers versus signals between two planes.
    √ Determine which nets should be terminated as transmission lines.

Circuit Board Layout to Reduce
Electromagnetic Emission and Susceptibility

A 5-Hour Video Presentation by Dr. Tom Van Doren

Program Description

The course covers circuit board layout issues that span the frequency range from DC to several GHz. Mixed analog and digital designs, and multilayer boards are emphasized. Most of the concepts and techniques presented are applicable to one- and two-sided board designs. Several key concepts are illustrated with demonstrations. You will also learn techniques for diagnosing electromagnetic interference problems at the board level.

This course shows that the issues of safety, emission, and susceptibility can be used to determine if, where, and how to connect the circuit board to a metal enclosure. Each specific case has its own unique result, but all conclusions are based on the same electromagnetic compatibility principles.

 Benefits

This course will help you to:

  • Design or manufacture electronic equipment;
  • Design printed circuit boards;
  • Design metal enclosures for circuit boards;
  • Select connectors and cables attached to circuit boards;
  • Design integrated circuits and packages;
  • Design filters to reduce conducted emissions;
  • Select heat sinks for integrated circuit packages; and,
  • Test for electromagnetic compatibility of products containing circuit boards.

 Learning Objectives

  • Explain why wiring inductance is more important than resistance
  • Describe how current loop area is related to self inductance
  • Explain how resonances worsen circuit board emission and immunity
  • Determine which nets should be terminated as transmission lines
  • Describe the four noise-coupling mechanisms
  • Describe two ways to reduce each of the four coupling mechanisms
  • Explain the two reasons for grounding
  • Explain the difference between a grounding conductor and a signal return conductor
  • Explain why a signal should be grounded to an external metal enclosure
  • Explain when to use series blocking and shunt diverting filter techniques
  • Understand the problem with mutual inductance for shunt capacitors
  • Recognize trace layouts that have excessive inductance
  • Design more effective DC power-distribution busses
  • Understand the advantages of alternative layer stack up configurations

Course Outline

Session 1:

1.  Introduction
2.  Signal Routing and the Path of Least Impedance
3.  Transmission Line Effects

Session 2:

4. Transmission Line Effects (continued)
5.  Noise Coupling Mechanisms

Session 3:

6.  Circuit Board Grounding Issues
7.  Filtering Conducted Noise

Session 4:

8.  DC Power Distribution and Decoupling

Session 5:

9.  Component Placement and Layer Stack up
10.  Chassis, Cable, and System Issues
11.  Review of EMC Principles and Board Layout Guidelines

APPENDIX 1. A Review of Background Material
APPENDIX 2. A Summary of EMC Guidelines for Circuit Board Layout

Registration

Fees:
$800

Registration Form (pdf)

Registration Contact:
Missouri S&T
Distance and Continuing Education
300 W. 12th Street
216 Centennial Hall
Rolla, MO  65409
Phone: 573-341-4200
Fax: 573-341-4992
Email: dce@mst.edu

Technical Contact:
Dr. Thomas Van Doren
Missouri S&T
Electrical & Computer Engineering
EMC Lab
Rolla, MO  65409
Phone: 573-341-4097
Email: vandoren@mst.edu