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EMI/EMC and Signal Integrity Boot Camp

Course 249

This course includes measurement demonstrations in the classroom.

Summary

This special five day workshop covers the methodology of designing and/or troubleshooting an electronic product to minimize the possibility of electromagnetic interference (EMI), signal integrity (SI) and/or Electromagnetic Compatibility (EMC) problems. The basics of designing electronic products with EMI, SI and EMC in mind are introduced in a very understandable and entertaining style.

The course is intended to cover the material from courses #243 (Signal Integrity and EMI Fundamentals) and #230 (EMI/EMC Design and Troubleshooting) as a comprehensive program including examples and simple experiments. The course presents the ways in which an electronic system can generate and/or receive EMI, thereby causing failure to meet EMC regulations. A practical approach with many real world examples, techniques, simulation and hardware tools for EMI/SI design will be explained to minimize costs, production and marketing delays by considering key factors and techniques in the design phase.

No prior EMI/SI knowledge is needed but an electrical engineering background (BSEE or equivalent experience) is recommended.

The five day course has a very practical approach through many real world examples, techniques, simulation and hardware demos:

  • Fundamentals
  • Basics Of Emi/Emc
  • High Speed/Frequency Effects In Electronic Circuits
  • Components In Rf/Emi/Emc/Si
  • Transmission Lines: Controlling Propagation
  • Matching
  • Signal Integrity Parameters
  • Grounding
  • Filtering
  • Printed Circuit Boards (PCBs)
  • Shielding
  • Cables
  • Transients
  • Diagnostic And Troubleshooting Techniques

DAY 1 is dedicated to the BASICS OF EMI/EMC/SI including coupling mechanisms, why to consider EMC, typical sources and victims, time domain vs. frequency domain, near vs. far field, non ideal components, controlling signal return currents, differential vs. common mode currents, radiation and pickup from loop and dipoles, the “hidden schematic” idea, etc. Scattering parameters (s-parameters) are presented as a very useful set of parameters for experimental characterization and design.

DAY 2 is dedicated to a review of COMPONENTS IN THE HIGH FREQUENCY/speed domain. TRANSMISSION LINES are explained in a very practical approach as a way to control signal propagation and impedance. Finally, MATCHING techniques are explained with many examples to obtain optimum power transfer and to avoid reflections.

DAY 3 is dedicated to the basics of SIGNAL INTEGRITY in electronic circuits including undesired effects, propagation time and delay, reflections and ringing, crosstalk (near and far) and jitter. Delays. Jitter. After SI basics, a key topic is presented: GROUNDING. Signal ground versus safety ground, grounding strategies, ground loops, techniques to minimize ground impedance are discussed. Finally principles of FILTERING are explained: reflection vs. dissipation, source and load influence, damping resonances and ringing, insertion losses, components and layout in filters, ferrites, decoupling and bypass, mains filters, filter mounting and layout.

DAY 4 covers the DESIGN OF PCBS, component selection and placement, special components for EMI (e.g. spread spectrum clocks), typical problems, layers (how many and distribution), layout, traces, transmission line effects, ground planes, splits in planes, decoupling (how, where, distributed, resonances, etc), crosstalk and examples. We will cover the topic of SHIELDING: influence of material, shielding effectiveness, low frequency magnetic fields, how to destroy a shield, holes and slots, gaskets, evaluation of shields, shield penetrations (how to do).

DAY 5 is dedicated to CABLES from EMI/SI point of view including how they can radiate or pick-up (they are antennas), shielded cables, cable grounding, connectors, types of cables (wires, twisted pairs, coax, shielded cables, ribbon cables, etc) and their influence in the EMC profile of the product. A review of TRANSIENTS and protection (including ESD basics) is presented. Finally simple instrumentation and DIAGNOSTIC AND TROUBLESHOOTING TECHNIQUES for EMI/EMC/SI problems are discussed.

Learning objectives

Upon completing the course you will be able to:

  • understand the basics and fundamentals of EMI, EMC and SIGNAL INTEGRITY (SI) issues.
  • look at high frequency fundamentals of EMI/SI, modeling problems to propose solutions.
  • design electronic equipment to avoid common EMI/EMC/SI failures.
  • use EMI diagnostic and troubleshooting techniques to locate and fix EMI/EMC problems in completed equipment designs.
  • locate and fix EMI/SI/EMC problems in a product or installation.
  • perform simple prequalification EMC tests.
  • reduce time and cost of EMI/SI diagnostics and fixes.

Target Audience

This course will be of interest to:

  • design engineers/technicians from the electronics industry involved in EMI and SIGNAL INTEGRITY (SI) problems.
  • those interested in a working knowledge of EMI/SI engineering principles and concerned with EMI/SI problems as high speed digital designers, RF designers and PCB layout engineers.
  • managers responsible for design, production, test and marketing of electronic products.
  • marketing engineers who need a general and practical knowledge of the EMI/SI basics.
  • design and test engineers/technicians from the electronics industry involved in EMI/EMC/SI problems. Analog, digital, RF, mechanical and system engineers and technicians interested in design process to avoid EMC problems.
  • those interested in a working knowledge of EMI/EMC engineering principles and concerned with EMC regulations.
  • laboratory personnel involved in measurement and troubleshooting of EMC failures.
  • managers responsible for design, production, test and marketing of electronic products.
  • marketing engineers who need a general and practical knowledge of the EMI/EMC basics.

Outline

Fundamentals

Back to Basics
 • Electrical signals • Maxwell vs. Kirchhoff: limits of circuit theory • Spectrum of a signal: time domain vs. frequency domain • Decibel and logarithmic scales • Resonance • Quality factor (Q) both loaded and unloaded • Bandwidth • Impedance matching definition • Frequency vs. dimensions (size) • Time vs. distance • Scattering parameters (s-parameters) • Typical formats and how to measure them

Basics of EMI/EMC

An introduction to the Electromagnetic Compatibility Problem
 • Why EMI affects electronic systems, examples • EMC: legal requirements • EMI/EMC classification (1) - radiated vs. conducted • EMI/EMC classification (2) - emissions vs. immunity • Source and victim and coupling mechanisms • EMI/EMC tests basics - emissions and immunity/susceptibility

High Speed/Frequency Effects in Electronic Circuits

How to think in high frequency
 • High speed and RF effects - attenuation, gain, loss and distortion • Skin effect, return current and parasitic effects • The importance of rise time and fall times (dv/dt and di/dt) • Key factors for EMI • Controlling signal return currents • Differential vs. common mode currents • EMI coupling mechanisms • Non ideal components • The “hidden schematic” concept • Antenna basics - dipoles and loops • Antenna resonance • Antenna gain • Antenna matching • Antenna radiation pattern • Near vs. far field • Low and high impedance signals and circuits • “Hidden antennas”: radiation and pickup

Components in RF/EMI/EMC/SI

When a capacitor is an inductor
 • Resistors, capacitors and inductors • Ferrites • Transformers • Diodes • Transistors • ICs • Digital and high speed circuits • Key parameters: power, speed and package • es, cables and connections basics • Transmission lines basics • Lumped vs. distributed systems • PCB structures • Vias (effects and modeling in high frequency) • Switches • Heat sinks • Shielding components

Transmission Lines

Controlling Propagation. Controlling Impedance
 • Wiring and connecting components - limitations for high frequency and high speed systems • What is a transmission line? • Motivation: signal propagation • Modeling a transmission line • Characteristic impedance and velocity of propagation • General description of typical transmission lines - coax, pairs, microstrip and stripline • Reflection coefficient • Standing Wave Ratio (SWR, VSWR and ISWR) and Return loss • Intuitive explanation • Examples from real world

Matching

Avoiding Reflections. Achieving Maximum Power Transfer
 • Maximum transfer of power and avoiding reflections • Matching with LC components • Matching networks • L, PI and T networks • Matching in narrow and broadband applications • Matching with transformers • Matching with transmission lines • rminations to avoid SI/EMI problems: solutions and techniques • Using software to design a matching network • Examples from real world

Signal Integrity Parameters

How Your Signal is Destroyed
 • What is Signal Integrity (SI) in electronic circuits? • Undesired effects • Propagation time and delay • Reflections and ringing • Inductive vs. capacitive coupling: crosstalk (near and far). • Delays • Jitter • Ground bounce • Power supply noise • Common mode impedance • High frequency, dv/dt and di/dt

Grounding

99% of Our Problems Come from the Ground System Design
 • Signal ground vs. safety ground • Ground in high frequency/speed applications: low impedance path • Minimizing ground impedance • Common impedance • Ground strategies (single point, multipoint, and hybrid) • Ground loops

Filtering

How to Process Your Signal from an Analog Point of View
 • Basic ideas • Filters for known impedances (no EMI applications) • Basic design techniques with examples • Filters for EMI/EMC • How filters work: reflection vs. dissipation • Insertion losses • Source and load influence • Parasitic and location effects • Filtering with ferrites • Saturation and undesired coupling effects • Decoupling and bypass fundamentals • Damping resonances and ringing • Three terminal and feed through components • Mains filters (differential mode and common mode) • filter mounting and layout

Printed Circuit Boards (PCBs)

Problems Start in Your PCB Design
 • Basic ideas • Typical problems in PCBs • Design strategy • Partitioning and critical zones • PCB structures (dielectric materials, structures, dissipation factor) • Choosing the PCB structure: how many layers and distribution • Power planes design and distribution • Layout and routing (1, 2 and multilayer) techniques - traces - microstrip and stripline - corners - vias - controlling impedance for SI - transmission line effects and solutions • Ground planes • Splits or ground discontinuities in planes (slots) • Decoupling and bypass (how, where, resonances, etc) - discrete capacitors vs. embedded techniques in high speed/RF designs • Crosstalk and guards • How ground plane layout affects crosstalk • Mixed signal PCBs (A/D designs) • Controlling clock waveform • Clock distribution • Clock shielding • Examples from real world

Shielding

It's Easy to Destroy Your Shielding System
 • Basic ideas • how shields work: reflection vs. absorption • Influence of material, shielding effectiveness • Low vs. high frequency fields, electric vs. magnetic fields • How to destroy a shield - holes and slots - shield penetrations - holes for fans and displays • Gaskets • Evaluation of shields • Shields and paint (for good and bad results) • transformer stray fields and real world examples

Cables

Paths for Your Signals. Hidden Antennas
 • Cable fundamentals • Types of cables - wires, twisted pairs, coax, shielded cables, ribbon cables, etc • Cable impedance • Shielded cables and cable grounding • Connectors • Cables as antennas for emissions and pickups • Avoiding crosstalk and reflections in cables (layout and terminations) • Avoiding common impedance in cables • Reducing emissions and pick-up in cables • Examples from real world

Transients

The World is not Ideal. Are You Ready to Protect Your Circuits?
 • Transients from natural and human sources • Typical transient problems - energy from inductance, ESD basics and high switching activity • Methods for transient protection - filtering, clamping and crowbar • Firmware and transients

Diagnostic and Troubleshooting Techniques

Being Sherlock Holmes to Find the Culprit
 • Useful tools and instruments - voltage probes, current probes, near field probes • Measuring voltage - Scope and probe limitations • Measuring current - probe response and transfer impedance • Diagnostic and troubleshooting techniques and hints • Locating EMI sources with near field probes • Examples from real world