Conception CEM perfectionnement (Module 2)

Goals

formation-objectifs-seointro Conception CEM perfectionnement (Module 2) :

At the end of this training course, trainees will be able to take into account all the key parameters involved in designing equipment that uses transitions of less than a nanosecond. They will know how to handle fast digital differential links, high-bandwidth or low-noise analogue links, and how to deal with EMC and functionality issues.

The aim of this training course is to:
- Master the initial design choices
- Master the EMC of components
- Understand transmission line effects and master their implementation
- Understand and adapt LF and HF protection solutions
- Be able to understand and master printed circuit board routing

Program

1 - Introduction: Reminders

• EMC expertise within the company


• Project EMC monitoring (1)


• Common mode and differential mode


• Low frequency / High frequency


• Spectral envelope of repetitive pulses


• Spectral density of a pulse


• Earth/ground/0 V symbols


• EMC couplings


• Common impedance coupling on a board


• Reducing track inductance through geometry


• Capacitive coupling between board and chassis


• Coupling through crosstalk


• Calculation ofloop voltage


• Current collected by a dipole


• Resonant circuits


• Forms

2 - Characteristics of passive components

• Impedance of a resistor


• Single pulse resistance of a resistor


• Resistor immunity


• Impedance of non-polarised capacitors


• Silicon capacitors


• Impedance of an inductor


• Power inductors


• Real and imaginary magnetic permeability


• High-micro ferrites


• Choosing a ferrite bead


• Measurements or modelling?


•  Modelling a common mode filter


• Comparison of measurement and modelling

3 - Filters

• Transfer function and insertion loss


• Insertion loss of an MC power filter


• Insertion loss of an MD power filter


• Identification of disturbances (BE or BL)


• RéResponse of a 2nd order low-pass filter


• Damping of the resonance of an L-C


• Damped sinusoidal pulses


• Damped cosine pulses 
  
  Pulse filtering


• Impulse responses of low-pass filters


• Passive low-pass filtering at input


• Digital signal filtering


• Filtering of sensors/power supplies


• Protection of digital inputs


• Protection of analogue inputs


• Surge protection


• Immunity to long-term overvoltage


• Voltage at the terminals of a Transzorb


• Transzorb: Peak power curve


• Current duration in a Transzorb

4 - Cables and connectors

• Low-frequency MC rejection through insulation


• Amplitude and phase of a low-pass R - C filter


• Differential asymmetry due to phase shift


• Asymmetry of input filters


• UTP: Conversion of MC to MD


• STP: Conversion of MC to MD


• Measuring the asymmetry of a pair


• Balun asymmetry


• Asymmetry of 100Mbps Ethernet line transformers


• Asymmetry of a 100 BaseTX Ethernet card


• Twisted pairs: shielded or unshielded?


• UTP or STP: calculating radiation immunity and conduction


• Principle of the reducing effect


• Simple measurement of the reduction effect of a screen


• Zt and shielding effectiveness measurements


• Zt of common cables


• Relationship between Zt and shielding effectiveness


• Transfer impedance of connectors


• Importance of grounding the base plates


• Reducing effect of a shielded pair


• Transmission of a low-voltage signal


• Low current signal transmission

5 - Characteristics of active components

• Linear chain noise


• Thermal noise (Johnson effect)


• Noise in 1 / F (excess noise)


• Principle of envelope detection


• Frequency response of an OP amp


• Output impedance of an op amp


• Output current and crossover distortion


• Characterisation of the output stage of an op amp


• Immunity of a digital isolator


• Risks of transistor oscillations in UHF


• Static voltage noise margins


• Dynamic logic margin


• Risk of oscillation in high impedance state


• EMC of samplers – blockers


• Jitter: definitions and measurement


• Effect of clock jitter on ADCs/DACs


• The latch-up phenomenon


• Integrated protection against DES


• Beware of discrepancies between dual sources


• Typical protection of inputs/outputs by diodes

6 - EMC of integrated circuits

• « Road Map » for VLSI circuits


• Noise and coupling in ASICs


• Origins of dI / dt


• Mastering the effects of dI / dt


• Common mode effect of dI / dt


• Calculating the number of Vcc / 0 V pairs


• Clock distribution


• Output driver sizing


• Beware of ‘pin-to-pin compatible’ enclosures

7 - Printed circuits

• Noise budget


• Optimal distribution of PCB layers


• Impedance of a copper plate


• Impédance of a finite/infinite 0 V plane


• Return current in a ground plane


• Impedance of finite 0 V planes


• Slot in a ground plane


• Noise from a split 0 V plane


• Effects of holes in a ground plane


• Return of current from a plug changing layers


• Measuring mass noise: precautions


• The three types of guard rings (or tracks)


• Radiated disturbances from a converter


• Sources of problems in radiated emissions


• Role and calculation of snubbers


• Practical development of a damper (R - C)


• Bead made of highly permeable material

8 - Lines

• Line: equivalent diagram


• Typical line characteristics


• Practical measurement of line impedance


• Maximum line length without adaptation


• Serial adaptation


• Parallel adaptation circuits


• Losses in a line due to skin effect


• Measurements and coaxial cables


• MC vs MD: different propagation speeds

Capacitive crosstalk and inductance on CIP