Electromagnetic Compatibility Engineering

Electromagnetic Compatibility Engineering......Page 5
CONTENTS......Page 9
Preface......Page 25
PART 1 EMC THEORY......Page 29
1.2 Noise and Interference......Page 31
1.3 Designing for Electromagnetic Compatibility......Page 32
1.5.1 FCC Regulations......Page 34
1.5.2 FCC Part 15, Subpart B......Page 36
1.5.3 Emissions......Page 39
1.5.4 Administrative Procedures......Page 42
1.5.6 Medical Equipment......Page 45
1.5.7 Telecom......Page 46
1.6 Canadian EMC Requirements......Page 47
1.7.1 Emission Requirements......Page 48
1.7.2 Harmonics and Flicker......Page 50
1.7.4 Directives and Standards......Page 51
1.8 International Harmonization......Page 54
1.9 Military Standards......Page 55
1.10 Avionics......Page 56
1.12 Typical Noise Path......Page 58
1.13.1 Conductively Coupled Noise......Page 59
1.13.2 Common Impedance Coupling......Page 60
1.14.1 Galvanic Action......Page 61
1.14.3 Triboelectric Effect......Page 63
1.15 Use of Network Theory......Page 64
Summary......Page 66
Problems......Page 67
References......Page 69
Further Reading......Page 70
2. Cabling......Page 72
2.1 Capacitive Coupling......Page 73
2.2 Effect of Shield on Capacitive Coupling......Page 76
2.3 Inductive Coupling......Page 80
2.4 Mutual Inductance Calculations......Page 82
2.5 Effect of Shield on Magnetic Coupling......Page 84
2.5.1 Magnetic Coupling Between Shield and Inner Conductor......Page 86
2.5.2 Magnetic Coupling—Open Wire to Shielded Conductor......Page 89
2.6 Shielding to Prevent Magnetic Radiation......Page 92
2.7 Shielding a Receptor Against Magnetic Fields......Page 95
2.8 Common Impedance Shield Coupling......Page 97
2.9 Experimental Data......Page 98
2.10 Example of Selective Shielding......Page 102
2.12 Coaxial Cable Versus Twisted Pair......Page 103
2.13 Braided Shields......Page 107
2.14 Spiral Shields......Page 109
2.15.1 Pigtails......Page 112
2.15.2 Grounding of Cable Shields......Page 116
2.16 Ribbon Cables......Page 122
Summary......Page 124
Problems......Page 126
References......Page 131
Further Reading......Page 132
3. Grounding......Page 134
3.1 AC Power Distribution and Safety Grounds......Page 135
3.1.1 Service Entrance......Page 136
3.1.2 Branch Circuits......Page 137
3.1.3 Noise Control......Page 139
3.1.4 Earth Grounds......Page 142
3.1.5 Isolated Grounds......Page 144
3.1.6 Separately Derived Systems......Page 146
3.1.7 Grounding Myths......Page 147
3.2 Signal Grounds......Page 148
3.2.1 Single-Point Ground Systems......Page 152
3.2.2 Multipoint Ground Systems......Page 154
3.2.3 Common Impedance Coupling......Page 156
3.2.4 Hybrid Grounds......Page 158
3.2.5 Chassis Grounds......Page 159
3.3 Equipment/System Grounding......Page 160
3.3.2 Clustered Systems......Page 161
3.3.3 Distributed Systems......Page 168
3.4 Ground Loops......Page 170
3.5 Low-Frequency Analysis of Common-Mode Choke......Page 175
3.6 High-Frequency Analysis of Common-Mode Choke......Page 180
3.7 Single Ground Reference for a Circuit......Page 182
Summary......Page 183
Problems......Page 184
Further Reading......Page 185
4.1 Balancing......Page 186
4.1.1 Common-Mode Rejection Ratio......Page 189
4.1.2 Cable Balance......Page 193
4.1.4 Balanced Loads......Page 194
4.2.1 Common-Mode Filters......Page 202
4.2.2 Parasitic Effects in Filters......Page 205
4.3 Power Supply Decoupling......Page 206
4.3.1 Low-Frequency Analog Circuit Decoupling......Page 211
4.3.2 Amplifier Decoupling......Page 213
4.4 Driving Capacitive Loads......Page 214
4.5 System Bandwidth......Page 216
Summary......Page 218
Problems......Page 219
References......Page 220
Further Reading......Page 221
5.1 Capacitors......Page 222
5.1.1 Electrolytic Capacitors......Page 223
5.1.2 Film Capacitors......Page 225
5.1.3 Mica and Ceramic Capacitors......Page 226
5.1.4 Feed-Through Capacitors......Page 228
5.1.5 Paralleling Capacitors......Page 230
5.2 Inductors......Page 231
5.3 Transformers......Page 232
5.4 Resistors......Page 234
5.4.1 Noise in Resistors......Page 235
5.5 Conductors......Page 236
5.5.1 Inductance of Round Conductors......Page 237
5.5.2 Inductance of Rectangular Conductors......Page 238
5.5.3 Resistance of Round Conductors......Page 239
5.5.4 Resistance of Rectangular Conductors......Page 241
5.6 Transmission Lines......Page 243
5.6.1 Characteristic Impedance......Page 245
5.6.2 Propagation Constant......Page 248
5.6.3 High-Frequency Loss......Page 249
5.6.4 Relationship Among C, L and ε(r)·......Page 252
5.7 Ferrites......Page 253
Summary......Page 261
Problems......Page 262
Further Reading......Page 265
6.1 Near Fields and Far Fields......Page 266
6.2 Characteristic and Wave Impedances......Page 269
6.3 Shielding Effectiveness......Page 271
6.4 Absorption Loss......Page 273
6.5 Reflection Loss......Page 277
6.5.1 Reflection Loss to Plane Waves......Page 280
6.5.2 Reflection Loss in the Near Field......Page 281
6.5.3 Electric Field Reflection Loss......Page 282
6.5.4 Magnetic Field Reflection Loss......Page 283
6.5.6 Multiple Reflections in Thin Shields......Page 284
6.6.1 Plane Waves......Page 285
6.6.2 Electric Fields......Page 286
6.6.3 Magnetic Fields......Page 287
6.8 Shielding with Magnetic Materials......Page 288
6.9 Experimental Data......Page 293
6.10 Apertures......Page 295
6.10.1 Multiple Apertures......Page 298
6.10.2 Seams......Page 301
6.10.3 Transfer Impedance......Page 305
6.11 Waveguide Below Cutoff......Page 308
6.12 Conductive Gaskets......Page 310
6.12.1 Joints of Dissimilar Metals......Page 311
6.12.2 Mounting of Conductive Gaskets......Page 312
6.13 The "IDEAL" Shield......Page 315
6.14.1 Transparent Conductive Coatings......Page 316
6.15 Conductive Coatings......Page 317
6.15.3 Vacuum Metalizing......Page 319
6.15.5 Metal Foil Linings......Page 320
6.16 Internal Shields......Page 321
6.17 Cavity Resonance......Page 323
Summary......Page 324
Problems......Page 325
References......Page 327
Further Reading......Page 328
7.1 Glow Discharges......Page 330
7.2 Metal-Vapor or Arc Discharges......Page 331
7.3 AC Versus DC Circuits......Page 333
7.5 Contact Rating......Page 334
7.6 Loads with High Inrush Currents......Page 335
7.7 Inductive Loads......Page 336
7.8 Contact Protection Fundamentals......Page 338
7.9 Transient Suppression for Inductive Loads......Page 342
7.10.2 R–C Network......Page 346
7.10.3 R–C–D Network......Page 349
7.11 Inductive Loads Controlled by a Transistor Switch......Page 350
7.13 Contact Protection Selection Guide......Page 351
7.14 Examples......Page 352
Summary......Page 353
Problems......Page 354
Further Reading......Page 355
8.1 Thermal Noise......Page 356
8.2 Characteristics of Thermal Noise......Page 360
8.3 Equivalent Noise Bandwidth......Page 362
8.4 Shot Noise......Page 365
8.5 Contact Noise......Page 366
8.6 Popcorn Noise......Page 367
8.7 Addition of Noise Voltages......Page 368
8.8 Measuring Random Noise......Page 369
Summary......Page 370
Problems......Page 371
Further Reading......Page 373
9.1 Noise Factor......Page 374
9.2.1 Single-Frequency Method......Page 377
9.2.2 Noise Diode Method......Page 378
9.3 Calculating S/N Ratio and Input Noise Voltage from Noise Factor......Page 379
9.4 Noise Voltage and Current Model......Page 381
9.5 Measurment of V(n) and I(n)......Page 383
9.6 Calculating Noise Factor and S/N Ratio from V(n)–I(n)......Page 384
9.7 Optimum Source Resistance......Page 385
9.8 Noise Factor of Cascaded Stages......Page 388
9.9 Noise Temperature......Page 390
9.10 Bipolar Transistor Noise......Page 392
9.10.1 Transistor Noise Factor......Page 393
9.10.2 V(n)–I(n) for Transistors......Page 395
9.11.1 FET Noise Factor......Page 396
9.12 Noise in Operational Amplifiers......Page 398
9.12.1 Methods of Specifying Op-Amp Noise......Page 401
Summary......Page 403
Problems......Page 404
References......Page 405
Further Reading......Page 406
10. Digital Circuit Grounding......Page 407
10.3 Digital Logic Noise......Page 408
10.4 Internal Noise Sources......Page 409
10.5 Digital Circuit Ground Noise......Page 412
10.5.1 Minimizing Inductance......Page 413
10.5.2 Mutual Inductance......Page 414
10.5.3 Practical Digital Circuit Ground Systems......Page 416
10.5.4 Loop Area......Page 418
10.6 Ground Plane Current Distribution and Impedance......Page 419
10.6.1 Reference Plane Current Distribution......Page 420
10.6.2 Ground Plane Impedance......Page 428
10.6.3 Ground Plane Voltage......Page 436
10.6.4 End Effects......Page 437
10.7 Digital Logic Current Flow......Page 440
10.7.1 Microstrip Line......Page 442
10.7.2 Stripline......Page 443
10.7.3 Digital Circuit Current Flow Summary......Page 446
Summary......Page 447
Problems......Page 448
References......Page 449
Further Reading......Page 450
PART 2 EMC APPLICATIONS......Page 451
11.1 Power Supply Decoupling......Page 453
11.2 Transient Power Supply Currents......Page 454
11.2.1 Transient Load Current......Page 455
11.2.2 Dynamic Internal Current......Page 456
11.2.3 Fourier Spectrum of the Transient Current......Page 457
11.3 Decoupling Capacitors......Page 459
11.4 Effective Decoupling Strategies......Page 464
11.4.2 Multiple Capacitors of the Same Value......Page 465
11.4.3 Multiple Capacitors of Two Different Values......Page 468
11.4.4 Multiple Capacitors of Many Different Values......Page 472
11.4.5 Target Impedance......Page 473
11.4.6 Embedded PCB Capacitance......Page 475
11.4.7 Power Supply Isolation......Page 480
11.5 The Effect of Decoupling on Radiated Emissions......Page 482
11.6 Decoupling Capacitor Type and Value......Page 484
11.7 Decoupling Capacitor Placement and Mounting......Page 485
11.8 Bulk Decoupling Capacitors......Page 487
11.9 Power Entry Filters......Page 488
Problems......Page 489
Further Reading......Page 491
12. Digital Circuit Radiation......Page 492
12.1 Differential-Mode Radiation......Page 493
12.1.3 Fourier Series......Page 496
12.1.4 Radiated Emission Envelope......Page 498
12.2.1 Board Layout......Page 499
12.2.2 Canceling Loops......Page 502
12.2.3 Dithered Clocks......Page 503
12.3 Common-Mode Radiation......Page 505
12.4 Controlling Common-Mode Radiation......Page 508
12.4.1 Common-Mode Voltage......Page 509
12.4.2 Cable Filtering and Shielding......Page 510
12.4.3 Separate I/O Grounds......Page 513
Summary......Page 516
Problems......Page 517
References......Page 518
Further Reading......Page 519
13.1 Power Line Impedance......Page 520
13.1.1 Line Impedance Stabilization Network......Page 522
13.2 Switched-Mode Power Supplies......Page 523
13.2.1 Common-Mode Emissions......Page 526
13.2.2 Differential-Mode Emissions......Page 529
13.2.4 Rectifier Diode Noise......Page 537
13.3 Power-Line Filters......Page 539
13.3.2 Differential-Mode Filtering......Page 540
13.3.3 Leakage Inductance......Page 541
13.3.4 Filter Mounting......Page 544
13.3.5 Power Supplies with Integral Power-Line Filters......Page 547
13.3.6 High-Frequency Noise......Page 548
13.4 Primary-to-Secondary Common-Mode Coupling......Page 551
13.6 Power Supply Instability......Page 552
13.7 Magnetic Field Emissions......Page 553
13.8 Variable Speed Motor Drives......Page 556
13.9 Harmonic Suppression......Page 564
13.9.2 Active Power Factor Correction......Page 566
13.9.3 AC Line Reactors......Page 567
Summary......Page 569
Problems......Page 570
Further Reading......Page 572
14.1 Performance Criteria......Page 573
14.2 RF Immunity......Page 574
14.2.1 The RF Environment......Page 575
14.2.2 Audio Rectification......Page 576
14.2.3 RFI Mitigation Techniques......Page 577
14.3 Transient Immunity......Page 585
14.3.2 Electrical Fast Transient......Page 586
14.3.3 Lightning Surge......Page 587
14.3.4 Transient Suppression Networks......Page 588
14.3.5 Signal Line Suppression......Page 589
14.3.6 Protection of High-Speed Signal Lines......Page 592
14.3.7 Power Line Transient Suppression......Page 594
14.3.8 Hybrid Protection Network......Page 598
14.4 Power Line Disturbances......Page 600
14.4.1 Power Line Immunity Curve......Page 601
Summary......Page 603
Problems......Page 604
References......Page 606
Further Reading......Page 607
15.1 Static Generation......Page 608
15.1.1 Inductive Charging......Page 611
15.1.2 Energy Storage......Page 613
15.2 Human Body Model......Page 615
15.3 Static Discharge......Page 617
15.3.1 Decay Time......Page 618
15.4 ESD Protection in Equipment Design......Page 620
15.5 Preventing ESD Entry......Page 622
15.5.1 Metallic Enclosures......Page 623
15.5.2 Input/Output Cable Treatment......Page 627
15.5.3 Insulated Enclosures......Page 632
15.5.4 Keyboards and Control Panels......Page 635
15.7 ESD Grounding......Page 636
15.8 Nongrounded Products......Page 637
15.9 Field-Induced Upset......Page 638
15.9.2 Capacitive Coupling......Page 639
15.10 Transient Hardened Software Design......Page 640
15.10.1 Detecting Errors in Program Flow......Page 641
15.10.2 Detecting Errors in Input/Output......Page 642
15.10.3 Detecting Errors in Memory......Page 644
Summary......Page 645
Problems......Page 647
References......Page 648
Further Reading......Page 649
16.1.2 Keep Out Zones......Page 650
16.1.3 Critical Signals......Page 651
16.1.4 System Clocks......Page 652
16.2 PCB-to-Chassis Ground Connection......Page 653
16.3 Return Path Discontinuities......Page 654
16.3.1 Slots in Ground/Power Planes......Page 655
16.3.2 Split Ground/Power Planes......Page 656
16.3.3 Changing Reference Planes......Page 658
16.3.4 Referencing the Top and Bottom of the Same Plane......Page 661
16.3.6 Ground Fill......Page 662
16.4 PCB Layer Stackup......Page 663
16.4.1 One- and Two-Layer Boards......Page 664
16.4.2 Multilayer Boards......Page 665
16.4.3 General PCB Design Procedure......Page 681
Summary......Page 683
Problems......Page 685
Further Reading......Page 686
17.1 Split Ground Planes......Page 688
17.2 Microstrip Ground Plane Current Distribution......Page 690
17.3 Analog and Digital Ground Pins......Page 693
17.4 When Should Split Ground Planes Be Used?......Page 696
17.5 Mixed Signal ICs......Page 697
17.6 High-Resolution A/D and D/A Converters......Page 699
17.6.1 Stripline......Page 701
17.6.2 Asymmetric Stripline......Page 702
17.6.3 Isolated Analog and Digital Ground Planes......Page 703
17.7.1 Sampling Clocks......Page 704
17.7.2 Mixed-Signal Support Circuitry......Page 706
17.8 Vertical Isolation......Page 707
17.9.1 Power Distribution......Page 709
17.9.2 Decoupling......Page 710
17.10 The IPC Problem......Page 712
Summary......Page 713
Problems......Page 714
Further Reading......Page 715
18. Precompliance EMC Measurements......Page 716
18.2 Antennas Versus Probes......Page 717
18.3 Common-Mode Currents on Cables......Page 718
18.3.2 Cautions......Page 721
18.4 Near Field Measurements......Page 722
18.4.1 Test Procedure......Page 723
18.4.2 Cautions......Page 724
18.5 Noise Voltage Measurements......Page 725
18.5.1 Balanced Differential Probe......Page 726
18.6 Conducted Emission Testing......Page 728
18.6.1 Test Procedure......Page 730
18.6.2 Cautions......Page 731
18.6.3 Separating C-M from D-M Noise......Page 732
18.7 Spectrum Analyzers......Page 735
18.7.1 Detector Functions......Page 737
18.7.2 General Test Procedure......Page 738
18.8 EMC Crash Cart......Page 739
18.8.1 Mitigation Parts List......Page 740
18.9.2 Limits for 1-m Testing......Page 741
18.9.3 Antennas for 1-m Testing......Page 742
18.10.1 Radiated Immunity......Page 745
18.10.2 Conducted Immunity......Page 748
18.10.3 Transient Immunity......Page 749
18.11 Precompliance Power Quality Tests......Page 751
18.11.1 Harmonics......Page 752
18.11.2 Flicker......Page 753
18.12.1 Radiated Emission Margin......Page 754
18.12.2 Electrostatic Discharge Margin......Page 755
Summary......Page 756
Problems......Page 757
References......Page 758
Further Reading......Page 759
A.1 Properties of Logarithms......Page 761
A.2 Using the Decibel for Other than Power Measurements......Page 762
A.4 Absolute Power Level......Page 764
A.5 Summing Powers Expressed in Decibels......Page 766
B. The Ten Best Ways to Maximize the Emission from Your Product......Page 768
C. Multiple Reflections of Magnetic Fields in Thin Shields......Page 771
D.1 Basic Dipoles for Dummies......Page 774
D.2 Intermediate Dipoles for Dummies......Page 779
D.3.2 Dipole Resonance......Page 784
D.3.4 Theory of Images......Page 787
D.3.5 Dipole Arrays......Page 789
Summary......Page 791
Further Reading......Page 792
E.1 Inductance......Page 793
E.2 Loop Inductance......Page 795
E.2.1 Inductance of a Rectangular Loop......Page 796
E.3 Partial Inductance......Page 798
E.3.1 Partial Self-Inductance......Page 799
E.3.2 Partial Mutual Inductance......Page 801
E.3.4 Partial Inductance Applications......Page 804
E.3.5 Transmission Line Example......Page 806
E.4 Ground Plane Inductance Measurement Test Setup......Page 808
E.5 Inductance Notation......Page 813
References......Page 816
Further Reading......Page 817
F. Answers to Problems......Page 818
Index......Page 853