EMI/EMC for the Design Engineer

If you are a design engineer, it pays to know how and why EMI testing is conducted, as well as the typical causes of failure. This two-day course offers all of the EMI information needed for you to provide a compliant radiation/susceptibility product, including design considerations at CAE and CAD levels. Ways to prevent common EMI/EMC problems regarding power supplies, cables, connectors, slots, discontinuity of ground planes, and more are examined. Focus is on EMI and RFI issues regarding PCBs, computers, analog designs, and systems, as well as relevant EMI regulations in the U.S., the European Union, and Asia. Highlights include PCB radiation basics, radiation and bypass on PCBs, PCB radiation suppression techniques, grounding designs/filtering, crosstalk/termination, power and ground planes, antenna loops, spread spectrum clocking, and differential-mode and common-mode radiation.

The course is intended for digital logic engineers, system architects, EMC specialists, technicians, PCB layout professionals, IC designers, IC package designers, application engineers, anyone who works with high-speed digital logic, those who work with any digital logic implemented in the submicron processes that are becoming standard in the industry, engineering managers, and project managers.

Recommended Prerequisite

This course is for anyone who has worked with today’s ICs, high-speed designs, and PCB layouts. No advanced math is required, although participants will find it helpful to bring a scientific calculator to the course. The course is presented at a technical level that provides experienced designers with information to design and lay out a high-speed PCB, including designing so that it meets Signal Integrity (SI) and EMI.

Course Materials

The text, EMC for Product Designers, Tim Williams (Elsevier, 2001), and 170 pages of comprehensive lecture notes are distributed on the first day of the course. The notes are for participants only and are not for sale.

Coordinator and Lecturer

Robert Hanson, MSEE, President, Americom Seminars, Inc., Bremerton, Washington. Mr. Hanson has over 40 years of experience in the design manufacturing and test areas. His initial education was in industrial engineering (IE) and business administration. After receiving his BSEE/MSEE, he became highly involved in all aspects of electronic testing. As a digital design engineer at The Boeing Company, Rockwell, Honeywell, and Loral, Mr. Hanson designed and provided prototype operational analysis on many high-speed designs, including PCBs for AWACS, B1-B, 747-400, missiles, and ground support test equipment. He has played a very active role in automating the line, implemented robotics, participated in producibility studies, and automatic material handling. He has held positions responsible for overseeing and working in the CAE/CAD/CAT, JIT, simulation, and automatic assembly environments. He also has performed studies and headed research projects in the computer-integrated manufacturing environment. Mr. Hanson has extensive experience in the testing disciplines (both factory and field, commercial and military) and has been the testability overseer for Boeing Commercial Airline products.

Course Program

EMI, Source, Path and Receptor
Why all three must be present to have an EMI problem.

EMI Regulations
Standards for USA, Europe (EU), and Asia. Detailed description of all the test requirements, equipment to conduct the tests, and the governing bodies/committees that mandate the tests.

RFI, ESD, power disturbances, internal.

EMI Issues
Frequency, amplitude, time, impedance, dimensions.

EMI Regulations
Commercial, military, avionics, automotive, medical, communications.

Conducting an EMI Test
Pre-compliance, compliance testing, and post-audit testing. What uncertainty is and how it affects the test plan.

How the Tests are Conducted
The hardware instrumentation, layout, pass/fail criteria, and tips/techniques to pass all the following tests are covered. The test site also is defined, i.e., OATS, screen room, anechoic chamber, and TEM cell. The step-by-step sequence of how each test is conducted is detailed.

  • Conducted Emissions
  • Radiated Emissions
  • RF Immunity
  • Conducted RF Immunity
  • ESD
  • Lightening
  • Electrical Fast Transient

Interference Coupling Mechanism
Near/far field, coupling modes, and resonance. The importance of parts placement, proper terminations, and grounding.

RFI, EMI Regarding PCBs, Computers, Analog Designs, and Systems

Grounding Designs/Filtering
Single ground, modified and multipoint grounding, and which one should be used for your design.

CM Radiation
Why common mode (CM) is the major problem versus differential mode (DM).

Antenna Loops
Why antenna loops are the major cause of radiated emission failures for PCBs.

Basics of PCB Radiation
Why both lumped and distributive (transmission lines–TL) circuits radiate. Why a high-Q circuit radiates. Terminating a TL to minimize radiation. The capacitive load and why it causes radiation.

PCB Suppression Techniques
Terminations, filters, and devices: how they are used to suppress radiation.

Design for Immunity
Watchdog timers, offensive/defensive programming, checksum, Hamming, and other techniques. How intelligent software helps pass immunity testing.

Switching Mode Power Supplies (SMPS)
SMPS chopping frequency: the major cause of conducted emissions; filters: schematic configurations of harmonic filters; what happens when transients/ESD hit the SMPS mains; immunity concerns; screens and snubbers, and transformer winding.

Inductive/capacitive, forward/backward: how it occurs. Why it causes radiation and how it is minimized. How to minimize PCB antenna loops. Do vias cause radiation?

Power/Ground Planes
Splits, slots, moats, floats, drawbridge, how to design for minimizing emissions from power/ground planes. How to design for digital/analog (multibias) and single bias PCBs.

Picket Fences, The 20H Rule, and Cu Fills
What they can do to suppress emissions.

Ideal Stackups to be EMC

Spread Spectrum Clocking
Why it suppresses radiated emissions. Under what conditions it can be used. Is there a better method?

Bypass and Radiation on PCBs
Why use the 0201, Ycap, and four-terminal cap? Types of innerplane capacitance, and does innerplane capacitance help with emissions?

Interference Coupling Modes
Why ground bounce causes differential and common mode noise, and how that causes emissions.

Near/Far Field
Determining the breakpoint between them. What happens to the characteristic impedance at the breakpoint.

Differential/Common Coupling Modes and Resonance
The quarter-length resonant mode differences when the load impedance is very high versus very low.

Analog Circuitry
Transients, filtering, grounding and noise isolation. Opto couplers versus spin resistors: which is better?

Cables/Connectors Interfaces, Filtering, and Shielding

Capacitive and Magnetic Shielding
What the difference is and how the shield should be tied to ground for either case.

Why they radiate. Is the radiation through them predictable?

Shield Grounding
How shields should be tied to ground to minimize circulation current.

Cable Radiation
Radiation through the shield and at the connector bulkhead connection.

Shielding Types
When to use Cu and Al versus mu metal, steel, or permalloy.

Transfer Impedance
What it is. Why it is detrimental to shielding and how it is minimized.

Shielding Connection
Leakage: how to design a non-emission connection of a connector to a bulkhead.

Loss of Ground Plane in Cables
Why it causes crosstalk, radiation, reflections, and propagation delay.

Cables Configuration
What shielding/grounding techniques to use to minimize crosstalk and radiation.

Antenna Loops with Cable Connections
Why shielding pigtails cause emission non-compliance.

High-Speed Connectors
How they are configured to minimize skin effect, dielectric loss, crosstalk, and radiation.

Types of filters, their attenuation capability, and how they should be mounted.

Shielding versus Filtering
Cost tradeoffs versus attenuation capability: when should either or both be used?

Using Ferrites
Amperes Rule. Why they work so well for both DM and CM.

Filtering Mains Supply
Using capacitors, chokes, and torroids. Filtering both DM and CM noise.

Using Transients Suppressors on Mains and I/O Lines
Where TVSSs, Spark Gaps, Varistors, and Zeners should be used.

Radiation through Shields
Current density versus skin depth, incident versus reflected fields.

For more information contact the Short Course Program Office:
shortcourses@uclaextension.edu | (310) 825-3344 | fax (310) 206-2815