Circuit Board Layout to Reduce Electromagnetic Emission Susceptibility

Grounding and Shielding of Electronic Systems and
Circuit Board Layout to Reduce Electromagnetic Emission and Susceptibility

About the courses
Grounding and Shielding of Electronic Systems is a two-day course that uses basic principles to explain how to improve signal integrity and reduce electromagnetic interference in systems that involve multiple modules or circuit boards with a variety of interconnecting cables. Fundamental circuit, system, and electromagnetic concepts are all that are needed to diagnose and reduce most routing and interference problems. See course content and schedule.

Circuit Board Layout to Reduce Electromagnetic Emission and Susceptibility is a one-day course that uses the basic principles explained in the Grounding and Shielding course to show how to improve signal integrity and reduce interference at the circuit board level. See course content and schedule.

These courses can be taken individually or together.

The courses will explain why a signal ground is not the same as a signal return. Also, solutions for the numerous problems caused by wiring inductance will be described and demonstrated. The courses will emphasize logical diagnostic techniques for identifying the various types of interference and routing problems. Usually the correct identification of the problem is more difficult than the solution.

Why these courses?

Most engineers and technicians using or designing electronic systems have not had formal training concerning grounding and shielding techniques. Learning how to solve grounding and shielding problems on the job can be very expensive for the employer and frustrating for the engineer. Most of the electromagnetic and circuit principles involved are simple. However, the complexity of many systems masks the logic and simplicity of possible solutions.

These courses present an organized introduction to the fundamental principles, clarify troublesome terminology, and demonstrate many techniques for identifying and reducing signal integrity or electromagnetic interference problems.

Basic principles are emphasized

Electrical noise and signal integrity problems at the system, circuit board, or integrated circuit levels can be minimized if the following simple principles are clearly understood.

  • Every current eventually returns to its source, NOT to ground.
  • Currents take the path of least impedance, NOT least resistance.
  • Self-inductance is a property of a complete current loop, NOT an individual wire.
  • The current return path is NOT the current grounding connection.
  • There are only 4 noise coupling mechanisms that need to be understood and controlled.
  • A signal can provide its own shielding, if the current return path surrounds the outgoing path.

Course Notes

A detailed set of lecture notes is provided for each course. Each figure in the notes is accompanied by a written summary of the key comments stated in the lecture. The figures plus written comments provide a convenient format for later review of the course contents. The many practical examples discussed during the course provide an opportunity to practice the techniques described. The examples and demonstrations will allow participants to apply the concepts described in the course to specific problems of personal interest.

Key Concepts in These Courses

  • Why ground a circuit
  • How to ground a circuit
  • Signal ground is not the same as signal return
  • Reducing ground loop noise
  • Where to ground a cable shield
  • Grounding mixed analog and digital
  • The four noise coupling mechanisms
  • How to diagnose noise problems
  • What is the path of least impedance?
  • When to shield and when to filter
  • CM & DM filtering techniques
  • Filtering at MHz and GHz frequencies
  • Reducing pulse ringing and rounding
  • Transmission line concepts
  • Reducing DC power bus noise
  • Reducing emission and susceptibility
  • Cable selection guidelines
  • Circuit board layout guidelines

Which Course to Take

Take Grounding & Shielding if you are interested in the design, operation, or maintenance of analog or digital systems involving sensors, cables, signal processing, programmable controls, power distribution, automated equipment, high-speed logic, etc.; or if you're a mechanical designer interested in chassis, cable, or connector selection.

Take Circuit Board Layout if your main interest is the design or layout of circuits mounted on a printed circuit board and you have some prior knowledge of electromagnetic compatibility principles. This courses moves at a fast pace and assumes that you are familiar with the EMC principles presented in the Grounding and Shielding course.

Take Both Courses if you are interested in circuit board design or layout, but need a review of electromagnetic compatibility principles. There is some overlap between the two courses, but the duplication will help to reinforce the key concepts.

Method of Instruction

Dr. Van Doren will stress the fundamental principles involved in typical electrical interference and signal routing problems. The principles will be described as concepts rather than theoretical equations. The emphasis on concepts will make the courses useful for people with a wide range of experience. Several interference mechanisms and shielding techniques will be demonstrated. Questions and comments from the participants will be encouraged.

Please contact Tom Van Doren at 573-341-4097 or vandoren@mst.edu if you have any questions about the technical content of these courses or if you want to discuss an in-house p