Grounding & Shielding of Electronic Systems

How to diagnose and solve signal integrity and electrical noise problems

Presented by Dr. Tom Van Doren

 Course Content and Schedule

First Day
8:00 am Check-in and Refreshments
8:30 am to 5:00 pm

1. Current Routing & Least Impedance

  • Understanding wiring inductance
  • DEMO: Path of least impedance
  • Controlling the current return path

2. Interference Coupling Mechanisms

  • Review of the 4 coupling mechanisms
  • Ways to recognize the dominant mechanism
  • Equivalent circuit for each mechanism

3. Field Containment, Bandwidth, Balance & Resonance

  • Routing to provide field containment
  • DEMO: Fields emitted by a coaxial cable
  • Relating bandwidth to transition time
  • CM currents and impedance imbalance
  • Resonances in lumped & distributed circuits
  • DEMO: Predicting & reducing resonances

4. Grounding for Safety and Noise Reduction

  • Signal routing is not the same as grounding
  • Characteristics of a ground structure
  • Safety grounding examples
  • Single point versus a ground grid
  • Avoiding kHz ground loops
  • Grounding analog and digital circuits
  • Grounding signals to chassis for RF & ESD immunity and to reduce RF emissions

5. Interference Diagnostic Techniques

  • Diagnostic analysis & measurement tools
  • How to determine the dominant mechanism
  • The influence of circuit impedance
  • Diagnostic measurement techniques
  • Using current and E & H field probes

 

Second Day
8:00 am Refreshments
8:30 am to 5:00 pm
Review of First Day

6. Filtering to Reduce Conducted Noise

  • Current blocking & diverting strategies

  • Types of filters
  • CM and DM filter techniques
  • GHz filtering techniques
  • Reducing capacitor mutual inductance
  • When to use ferrite beads

7. Field Containment Using Self Shielding

  • The low cost & wide bandwidth approach
  • Signal routing provides the containment
  • DEMO: Twisted pair versus coax cable
  • Misuses of twisted pair

8. Reducing Capacitively Coupled Noise

  • DEMO: Capacitive shielding example
  • Capacitive noise reduction options
  • DEMO: Shield connection for twisted pair

9. Reducing Inductively Coupled Noise

  • Reducing mutual inductance
  • Eddy current shielding
  • Magnetic flux shunting
  • DEMO: Magnetic shielding option

10. Electromagnetic Wave Shielding

  • Skin effect & RF containment
  • Making cable shields effective at GHz
  • Sizing air flow openings
  • Controlling CM currents
  • EM containment is more important than grounding