Henry Ott Consultants
Electromagnetic Compatibility Consulting and Training
Electromagnetic Compatibility Engineering
by
Henry W. Ott
Detail Table of Contents
Preface
Part 1, EMC Theory
1. Electromagnetic Compatibility
1.1 Introduction
1.2 Noise and Interference
1.3 Designing for Electromagnetic Compatibility
1.4 Engineering Documentation and EMC
1.5 United States’ EMC Regulations
1.5.1 FCC Regulations
1.5.2 FCC Part 15, Subpart B
1.5.3 Emissions
1.5.4 Administrative Procedures
1.5.5 Susceptibility
1.5.6 Medical Equipment
1.5.7 Telecom
1.5.8 Automotive
1.6 Canadian EMC Requirements
1.7 European Union’s EMC Requirements
1.7.1 Emission Requirements
1.7.2 Harmonics and Flicker
1.7.3 Immunity Requirements
1.7.4 Directives and Standards
1.8 International Harmonization
1.9 Military Standards
1.10 Avionics
1.11 The Regulatory Process
1.12 Typical Noise Path
1.13 Methods of Noise Coupling
1.13.1 Conductively Coupled Noise
1.13.2 Common Impedance Coupling
1.13.3 Electric and Magnetic Field Coupling
1.14 Miscellaneous Noise Sources
1.14.1 Galvanic Action
1.14.2 Electrolytic Action
1.14.3 Triboelectric Effect
1.14.4 Conductor Motion
1.15 Use of Network Theory
Summary
Problems
References
Further Reading
2. Cabling
2.1 Capacitive Coupling
2.2 Effect of Shield on Capacitive Coupling
2.3 Inductive Coupling
2.4 Mutual Inductance Calculations
2.5 Effect of Shield on Magnetic Coupling
2.5.1 Magnetic Coupling Between Shield and Inner Conductor
2.5.2 Magnetic Coupling–Open Wire to Shielded Conductor
2.6 Shielding to Prevent Magnetic Radiation
2.7 Shielding a Receptor Against Magnetic Fields
2.8 Common Impedance Shield Coupling
2.9 Experimental Data
2.10 Example of Selective Shielding
2.11 Shield Transfer Impedance
2.12 Coaxial Cable Versus Twisted Pair
2.13 Braided Shield
2.14 Spiral Shields
2.15 Shield Terminations
2.15.1 Pigtails
2.15.2 Grounding of Cable Shields
2.16 Ribbon Cables
2.17 Electrically Long Cables
Summary
Problems
References
Further Reading
3. Grounding
3.1 AC Power Distribution and Safety Grounds
3.1.1 Service Entrance
3.1.2 Branch Circuits
3.1.3 Noise Control
3.1.4 Earth Grounds
3.1.5 Isolated Grounds
3.1.6 Separately Derived Systems
3.1.7 Grounding Myths
3.2 Signal Grounds
3.2.1 Single-Point Ground Systems
3.2.2 Multipoint Ground Systems
3.2.3 Common Impedance Coupling
3.2.4 Hybrid Grounds
3.2.5 Chassis Grounds
3.3 Equipment/System Grounding
3.3.1 Isolated Systems
3.3.2 Clustered Systems
3.3.3 Distributed Systems
3.4 Ground Loops
3.5 Low-Frequency Analysis of Common-Mode Choke
3.6 High-Frequency Analysis of Common-Mode Choke
3.7 Single Ground Reference For a Circuit
Summary
Problems
References
Further Reading
4. Balancing and Filtering
4.1 Balancing
4.1.1 Common-Mode Rejection Ratio
4.1.2 Cable Balance
4.1.3 System Balance
4.1.4 Balanced Loads
4.2 Filtering
4.2.1 Common-Mode Filters
4.2.2 Parasitic Effects in Filters
4.3 Power Supply Decoupling
4.3.1 Low-Frequency Analog Circuit Decoupling
4.3.2 Amplifier Decoupling
4.4 Driving Capacitive Loads
4.5 System Bandwidth
4.6 Modulation and Coding
Summary
Problems
References
Further Reading
5. Passive Components
5.1 Capacitors
5.1.1 Electrolytic Capacitors
5.1.2 Film Capacitors
5.1.3 Mica and Ceramic Capacitors
5.1.4 Feed-Through Capacitors
5.1.5 Paralleling Capacitors
5.2 Inductors
5.3 Transformers
5.4 Resistors
5.4.1 Noise in Resistors
5.5 Conductors
5.5.1 Inductance of Round Conductors
5.5.2 Inductance of Rectangular Conductors
5.5.3 Resistance of Round Conductors
5.5.4 Resistance of Rectangular Conductors
5.6 Transmission Lines
5.6.1 Characteristic Impedance
5.6.2 Propagation Constant
5.6.3 High-Frequency Loss
5.6.4 Relationship Among C, L, and εr
5.6.5 Final Thoughts
5.7 Ferrites
Summary
Problems
References
Further Reading
6. Shielding
6.1 Near Fields and Far Fields
6.2 Characteristic and Wave Impedances
6.3 Shielding Effectiveness
6.4 Absorption Loss
6.5 Reflection Loss
6.5.1 Reflection Loss to Plane Waves
6.5.2 Reflection Loss in the Near Field
6.5.3 Electric Field Reflection Loss
6.5.4 Magnetic Field Reflection Loss
6.5.5 General Equation for Reflection Loss
6.5.6 Multiple Reflections in Thin Shields
6.6 Composite Absorption and Reflection Loss
6.6.1 Plane Waves
6.6.2 Electric Fields
6.6.3 Magnetic Fields
6.7 Summary of Shielding Equations
6.8 Shielding With Magnetic Materials
6.9 Experimental Data
6.10 Apertures
6.10.1 Multiple Apertures
6.10.2 Seams
6.10.3 Transfer Impedance
6.11 Waveguide Below Cutoff
6.12 Conductive Gaskets
6.12.1 Joints of Dissimilar Metals
6.12.2 Mounting of Conductive Gaskets
6.13 The “Ideal” Shield
6.14 Conductive Windows
6.14.1 Transparent Conductive Coatings
6.14.2 Wire Mesh Screens
6.14.3 Mounting of Windows
6.15 Conductive Coatings
6.15.1 Conductive Paints
6.15.2 Flame/Arc Spray
6.15.3 Vacuum Metalizing
6.15.4 Electroless Plating
6.15.5 Metal Foil Linings
6.15.6 Filled Plastics
6.16 Internal Shields
6.17 Cavity Resonance
6.18 Grounding of Shields
Summary
Problems
References
Further Reading
7. Contact Protection
7.1 Glow Discharges
7.2 Metal-Vapor or Arc Discharges
7.3 AC Versus DC Circuits
7.4 Contact Material
7.5 Contact Rating
7.6 Loads With High Inrush Currents
7.7 Inductive Loads
7.8 Contact Protection Fundamentals
7.9 Transient Suppression for Inductive Loads
7.10 Contact Protection Networks for Inductive Loads
7.10.1 C Network
7.10.2 R-C Network
7.10.3 R-C-D Network
7.11 Inductive Loads Controlled by a Transistor Switch
7.12 Resistive Load Contact Protection
7.13 Contact Protection Selection Guide
7.14 Examples
Summary
Problems
References
Further Reading
8. Intrinsic Noise Sources
8.1 Thermal Noise
8.2 Characteristics of Thermal Noise
8.3 Equivalent Noise Bandwidth
8.4 Shot Noise
8.5 Contact Noise
8.6 Popcorn Noise
8.7 Addition of Noise Voltages
8.8 Measuring Random Noise
Summary
Problems
References
Further Reading
9. Active Device Noise
9.1 Noise Factor
9.2 Measurement of Noise Factor
9.2.1 Single-Frequency Method
9.2.2 Noise Diode Method
9.3 Calculating S/N Ratio and Input Noise Voltage From
Noise Factor
9.4 Noise Voltage and Current Model
9.5 Measurement of Vn and In
9.6 Calculating Noise Factor and S/N Ratio From Vn--In
9.7 Optimum Source Resistance
9.8 Noise Factor of Cascaded Stages
9.9 Noise Temperature
9.10 Bipolar Transistor Noise
9.10.1 Transistor Noise Factor
9.10.2 Vn-In for Transistors
9.11 Field-Effect Transistor Noise
9.11.1 FET Noise Factor
9.11.2 Vn-In Representation of FET Noise
9.12 Noise in Operational Amplifiers
9.12.1 Methods of Specifying Op-Amp Noise
9.12.2 Op-Amp Noise Factor
Summary
Problems
References
Further Reading
10. Digital Circuit Grounding
10.1 Frequency Versus Time Domain
10.2 Analog Versus Digital Circuits
10.3 Digital Logic Noise
10.4 Internal Noise Sources
10.5 Digital Circuit Ground Noise
10.5.1 Minimizing Inductance
10.5.2 Mutual Inductance
10.5.3 Practical Digital Circuit Ground Systems
10.5.4 Loop Area
10.6 Ground Plane Current Distribution and Impedance
10.6.1 Reference Plane Current Distribution
10.6.2 Ground Plane Impedance
10.6.3 Ground Plane Voltage
10.6.4 End Effects
10.7 Digital Logic Current Flow
10.7.1 Microstrip Line
10.7.2 Stripline
10.7.3 Digital Circuit Current Flow Summary
Summary
Problems
References
Further Reading
Part 2, EMC Applications
11. Digital Circuit Power Distribution
11.1 Power Supply Decoupling
11.2 Transient Power Supply Currents
11.2.1 Transient Load Current
11.2.2 Dynamic Internal Current
11.2.3 Fourier Spectrum of the Transient Current
11.2.4 Total Transient Current
11.3 Decoupling Capacitors
11.4 Effective Decoupling Strategies
11.4.1 Multiple Decoupling Capacitors
11.4.2 Multiple Capacitors of the Same Value
11.4.3 Multiple Capacitors of Two Different Values
11.4.4 Multiple Capacitors of Many Different Values
11.4.5 Target Impedance
11.4.6 Embedded PCB Capacitance
11.4.7 Power Supply Isolation
11.5 The Effect on Decoupling on Radiated Emissions
11.6 Decoupling Capacitor Type and Value
11.7 Decoupling Capacitor Placement and Mounting
11.8 Bulk Decoupling Capacitors
11.9 Power Entry Filters
Summary
Problems
References
Further Reading
12. Digital Circuit Radiation
12.1 Differential-Mode Radiation
12.1.1 Loop Area
12.1.2 Loop Current
12.1.3 Fourier Series
12.1.4 Radiated Emission Envelope
12.2 Controlling Differential-Mode Radiation
12.2.1 Board Layout
12.2.2 Canceling Loops
12.2.3 Dithered Clocks
12.3 Common-Mode Radiation
12.4 Controlling Common-Mode Radiation
12.4.1 Common-Mode Voltage
12.4.2 Cable Filtering and Shielding
12.4.3 Separate I/O Grounds
12.4.4 Dealing With Common-Mode Radiation Issues
Summary
Problems
References
Further Reading
13. Conducted Emissions
13.1 Power Line Impedance
13.1.1 Line Impedance Stabilization Network
13.2 Switched-Mode Power Supplies
13.2.1 Common-Mode Emissions
13.2.2 Differential-Mode Emissions
13.2.3 DC-To-DC Converters
13.2.4 Rectifier Diode Noise
13.3 Power-Line Filters
13.3.1 Common-Mode Filtering
13.3.2 Differential-Mode Filtering
13.3.3 Leakage Inductance
13.3.4 Filter Mounting
13.3.5 Power Supplies With Integral Power-Line Filters
13.3.6 High-Frequency Noise
13.4 Primary-to-Secondary Common-Mode Coupling
13.5 Frequency Dithering
13.6 Power Supply Instability
13.7 Magnetic Field Emissions
13.8 Variable Speed Motor Drives
13.9 Harmonic Suppression
13.9.1 Inductive Input Filters
13.9.2 Active Power Factor Correction
13.9.3 AC Line Reactors
Summary
Problems
References
Further Reading
14. RF and Transient Immunity
14.1 Performance Criteria
14.2 RF Immunity
14.2.1 The RF Environment
14.2.2 Audio Rectification
14.2.3 RFI Mitigation Techniques
14.3 Transient Immunity
14.3.1 Electrostatic Discharge
14.3.2 Electrical Fast Transient
14.3.3 Lightning Surge
14.3.4 Transient Suppression Networks
14.3.5 Signal Line Suppression
14.3.6 Protection of High-Speed Signal Lines
14.3.7 Power Line Transient Suppression
14.3.8 Hybrid Protection Network
14.4 Power Line Disturbances
14.4.1 Power Line Immunity Curve
Summary
Problems
References
Further Reading
15 Electrostatic Discharge
15.1 Static Generation
15.1.1 Inductive Charging
15.1.2 Energy Storage
15.2 Human Body Model
15.3 Static Discharge
15.3.1 Decay Time
15.4 ESD Protection in Equipment Design
15.5 Preventing ESD Entry
15.5.1 Metallic Enclosures
15.5.2 Input/Output Cable Treatment
15.5.3 Insulated Enclosures
15.5.4 Keyboards and Control Panels
15.6 Hardening Sensitive Circuits
15.7 ESD Grounding
15.8 Nongrounded Products
15.9 Field-Induced Upset
15.9.1 Inductive Coupling
15.9.2 Capacitive Coupling
15.10 Transient Hardened Software Design
15.10.1 Detecting Errors in Program Flow
15.10.2 Detecting Errors in Input/Output
15.10.3 Detecting Errors in Memory
15.11 Time Windows
Summary
Problems
References
Further Reading
16. PCB Layout and Stack-Up
16.1 General PCB Layout Considerations
16.1.1 Partitioning
16.1.2 Keep Out Zones
16.1.3 Critical Signals
16.1.4 System Clocks
16.2 PCB-to-Chassis Ground Connection
16.3 Return Path Discontinuities
16.3.1 Slots in Ground/Power Planes
16.3.2 Split Ground/Power Planes
16.3.3 Changing Reference Planes
16.3.4 Referencing the Top and Bottom of the Same Plane
16.3.5 Connectors
16.3.6 Ground Fill
16.4 PCB Layer Stackup
16.4.1 One- and Two-Layer Boards
16.4.2 Multilayer Boards
16.4.3 General PCB Design Procedure
Summary
Problems
References
Further Reading
17. Mixed-Signal PCB Layout
17.1 Split Ground Planes
17.2 Microstrip Ground Plane Current Distribution
17.3 Analog and Digital Ground Pins
17.4 When Should Split Ground Planes be Used?
17.5 Mixed Signal ICs
17.5.1 Multi-Board Systems
17.6 High-Resolution A/D and D/A Converters
17.6.1 Stripline
17.6.2 Asymmetric Stripline
17.6.3 Isolated Analog and Digital Ground Planes
17.7 A/D and D/A Converts Support Circuitry
17.7.1 Sampling Clocks
17.7.2 Mixed-Signal Support Circuitry
17.8 Vertical Isolation
17.9 Mixed-Signal Power Distribution
17.9.1 Power Distribution
17.9.2 Decoupling
17.10 The IPC Problem
Summary
Problems
References
Further Reading
18. Precompliance EMC Measurements
18.1 Test Environment
18.2 Antennas Versus Probes
18.3 Common-Mode Currents on Cables
18.3.1 Test Procedure
18.3.2 Cautions
18.4 Near Field Measurements
18.4.1 Test Procedure
18.4.2 Cautions
18.4.3 Seams and Apertures in Enclosures
18.5 Noise Voltage Measurements
18.5.1 Balanced Differential Probe
18.5.2 DC to 1-GHz Probe
18.5.3 Cautions
18.6 Conducted Emission Testing
18.6.1 Test Procedure
18.6.2 Cautions
18.6.3 Separating C-M From D-M Noise
18.7 Spectrum Analyzers
18.7.1 Detector Functions
18.7.2 General Test Procedure
18.8 EMC Crash Cart
18.8.1 Mitigation Parts List
18.9 One-Meter Radiated Emission Measurements
18.9.1 Test Environment
18.9.2 Limits For 1-m Testing
18.9.3 Antennas For 1-m Testing
18.10 Precompliance Immunity Testing
18.10.1 Radiated Immunity
18.10.2 Conducted Immunity
18.10.3 Transient Immunity
18.11 Precompliance Power Quality Tests
18.11.1 Harmonics
18.11.2 Flicker
18.12 Margin
18.12.1 Radiated Emission Margin
18.12.2 Electrostatic Discharge Margin
Summary
Problems
References
Further Reading
Appendix
A. The Decibel
A.1 Properties of Logarithms
A.2 Using the Decibel for Other Than Power Measurements
A.3 Power Loss or Negative Power Gain
A.4 Absolute Power Level
A.5 Summing Powers Expressed in Decibels
B. The Ten Best Ways to Maximize the Emission
from Your Product
C. Multiple Reflections of Magnetic Fields in
Thin Shields
D. Dipoles for Dummies
D.1 Basic Dipoles for Dummies
D.2 Intermediate Dipoles for Dummies
D.3 Advanced Dipoles for Dummies
D.3.1 Impedance of a Dipole
D.3.2 Dipole Resonance
D.3.3 Receiving Dipole
D.3.4 Theory of Images
D.3.5 Dipole Arrays
D.3.6 Very High-Frequency Antennas
Summary
Further Reading
E. Partial Inductance
E.1 Inductance
E.2 Loop Inductance
E.2.1 Inductance of a Rectangular Loop
E.3 Partial Inductance
E.3.1 Partial Self-Inductance
E.3.2 Partial Mutual-Inductance
E.3.3 Net Partial Inductance
E.3.4 Partial Inductance Applications
E.3.4.1 Rectangular Loop
E.3.4.2 Two Unequal Diameter Parallel Conductors
E.3.5 Transmission Line Example
E.4 Ground Plane Inductance Measurement Test Setup
E.5 Inductance Notation
Summary
References
Further Reading
F. Answers to Problems
Index
Return to top of page.
Return to HOC homepage.
Search Web Site
Henry Ott Consultants
48 Baker Road Livingston, NJ 07039
Phone: 973-992-1793, FAX: 973-533-1442
July 17, 2009