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EMC measurements of components

EMC measurements of components. Summary. EMC problem examples EM disturbance sources EMC certification ? EMC measurement for electronic systems EMC measurement for integrated circuits. June 14. EMC problem examples. A typical electromagnetic environment…. June 14. EMC problem examples.

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EMC measurements of components

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  1. EMC measurements of components

  2. Summary EMC problem examples EM disturbance sources EMC certification ? EMC measurement for electronic systems EMC measurement for integrated circuits June 14

  3. EMC problem examples A typical electromagnetic environment… June 14

  4. EMC problem examples Electromagnetic interference issues in medical devices • Medical device EMI problems reported by FDA between 1979 and 1993 http://www.emcs.org/acstrial/newsletters/fall04/63_67.pdf • 405 suspected EMI problems reported by FDA between 1994 and 2005, with 6 deaths, 170 injuries and 167 malfunctions. 72 % of cases concern implantable devices. June 14

  5. EMC problem examples Electromagnetic interference issues in military systems 29th July 1967 : accident of the American aircraft carrier USS Forrestal. The accidental launching of a rocket blew gas tank and weapon stocks, killing 135 persons and causing damages which needed 7 month reparations. Investigations showed that a radar induced on plane wiring a sufficient parasitic voltage to trigger the launching of the rocket. H.M.S. Sheffield catastrophe: “During the Falklands War, the British Ship H.M.S Sheffield sank after being hit by an Exocet missile. Despite the Sheffield having the most sophisticated antimissile defense system available, the system created EMI to radiocommunications to and among the contingent of Harrier jets assigned to the ship. While the Harriers took off, the missile defense was disengaged to allow communications with the jets and provided a window of opportunity for the Exocet missile.” June 14

  6. EMC problem examples Electromagnetic interference issues in automotive Interference Technology – October 2011 Mercedez-Benz case: “During the early years of ABS, Mercedez-Benz automobiles equipped with ABS had severe braking problems along a certain stretch of the German autobahn. The brakes were affected by a near-by-near radio transmitter as drivers applied them on the curved section of highway. The near-term solution was to a erect a mesh screen along the roadway to attenuate the EMI. This enabled the brakes to function properly when drivers applied them…. Eventually, automobile ABS was qualified by EMI testing prior to procurement.” June 14

  7. EMC problem examples Electromagnetic interference issues in aviation « Disturbances of flight instruments causing trajectory deviations appear when one or several passengers switch on electronic devices. » (Air et Cosmos, April 1993) NASA publication 1374 (1986 – 1995) FAA Aviation Safety Reporting System has reported 12 cases of interference in aircraft due to personal electronic devices since 2002. June 14

  8. EMC problem examples Electromagnetic interference issues in space aircraft Vacuum cleaner incident: “During a Spacelab mission in 1985, the crew decided to use the middeck vacuum cleaner instead of the one in the lab. Switching the middeck vacuum on caused the voltage to drop and the Remote Acquisition Unit to shut off. In preflight EMI tests, the vacuum cleaner had not been tested and should not have been used in the lab. This case shows how careful and attentive one must when dealing with EMC.” [Nasa Publication 1374] June 14

  9. EM disturbance sources Various disturbance sources that can affect electronic system operation Human activity Natural sources Intentional emission Non intentional emission Electrostatic discharge June 14

  10. EM disturbance sources Interferences from telecommunication systems Radio-navigation • Narrowband emission, modulated signals. • Regulation and planification of radioelectric spectrum controlled by ITU-R at international level, and by « Agence Nationale des Fréquences » (ANFR) at French level. June 14

  11. EM disturbance sources Interferences from electronic systems • Parasitic noise generated by the activity (switching) of any electrical or electronic devices • The noiise is usually impulse type  broadband noise. • Example : Radiated emission from a 16 bit microcontroller June 14

  12. EM disturbance sources The EM environment according to ITU-R 372-8 • Ambient field levels defined from EM survey in 70’s. • Recent surveys show a 20 – 40 dB increase in semi-enclosed environment. • Example: Survey of the average level of electric field in Canada during the 90’s in urban and suburban environment: between 1 and 20 V/m. June 14

  13. EM disturbance sources The EM environment • Site Agence Nationale des Fréquences (www.anfr.fr) – outil Cartoradio. Distance antenne – point de mesure = 60m Etot = 4.35 V/m Champ E June 14

  14. Summary • EM disturbances can induce major failures in electronic systems. • The parasitic emission and susceptibility to EM disturbances must be tested to ensure electromagnetic compatibility of an electronic systems within a nominal environment. • But it is a tedious task because: • Diversity in terms of electronic devices • Numerous types of disturbances (LF, HF, pulsed, modulated), numerous EM environment • Various EM coupling possibilities (conducted, radiated, near-field…) How defining generic tests to guarantee EMC for any electronic systems in any EM environment, with an industrial realism ? June 14

  15. The EMC certification CE mark EMC European Directive • The European directive 89/336/EEC (1996) and then 2004/108/EC (2004) requires that all « electrical apparatus » placed on the European market : • Do not produce electromagnetic interferences able to disturb radio or telecom equipments , and the normal operation of all equipments • Have a sufficient immunity level to electromagnetic interferences to prevent any degradation of the normal operation. • All manufacturers of « electrical apparatus » must certify that the directive is supposed respected by delivering a declaration of conformity and placing a CE mark on the product. • Using harmonized standards adapted to the product to verify the supposition of conformity is recommended June 14

  16. The EMC certification R&TTE European Directive • The European directive 99/5/EC (1999) Radio & Telecommunications Terminal Equipment which is applied to all telecom and radio equipments emitting on the band 9 KHz – 3000 GHz replace the EMC directive. . • R&TTE requires that telecom and radio equipments placed on the European market: : • Comply to safety constraints given by the Low Voltage directive (73/23/EEC) (e.g. the limit of EM exposure for persons) and the EMC constraints given by the EMC directive 2004/108/EC. • Radio equipments use spectral resources dedicated for terrestrial and spatial communications without generating any interferences. • R&TTE mark: Warning signal for class 2 equipments (special recommandations) Required for all equipments under the R&TTE directive June 14

  17. The EMC certification EMC normative bodies: the importance of EMC standards ! International European International Electrotechnical Commission(IEC) EuropeanCommitee for ElectrotechnicalStandardization(CENELEC) EuropeanTelecommunication Standards Institute (ETSI) Comité International Spécial des Perturbations Radioélectriques(CISPR) TC77 Harmonized standards EN 50XXX EN 55XXX EN 6XXXX CISPR-XX IEC 61000-X EN 300XX June 14

  18. The EMC certification Commercial harmonized standard (non exhaustive list !) June 14

  19. The EMC certification Commercial harmonized standard (non exhaustive list !) • Automotive, military, aerospace and railway industries have developed their own EMC standards. June 14

  20. The EMC certification Case study 1 • You want to place on the European market a ventilator for domestic installation. It is supplied by mains (220 V). • Which EMC standard(s) should you follow ? What tests should you conduct for the EMC certification ? June 14

  21. The EMC certification Case study 1 • Application of EN55014-1 and 2: “Electromagnetic compatibility – Requirements for household appliances, electric tools and similar apparatus” – Part 1 = Emission, Part 2 = Immunity : • Any domestic electric/electronic equipments, toys, electric tool supplied under 250 V (monophase) (motors, heat elements, thermostats …) • Except light modules (EN55015), radio receivers (EN55025), gaming machine (EN55022). 21 June 14

  22. The EMC certification Case study 2 • Suggested emission tests: • Suggested immunity tests: 22 June 14

  23. The EMC certification Case study 2 • You want to place on the European market a radio emitter/receiver for remote control application in residential environment. The radio emitter use the ISM band around 434 MHz. Its maximum radiated power is limited to 500 mW. The emitter/receiver is an handheld device. • Which EMC standard(s) should you follow ? What tests should you conduct for the EMC certification ? June 14

  24. The EMC certification Case study 2 • The harmonized standard EN 300220: “Electromagnetic compatibility and radio spectrum matters (ERM); Short Range devices (SRD); Radio equipment to be used in the 25 MHz to 1000 MHz frequency range with power levels ranging up to 500 mW” is adapted to short range devices : • either with a Radio Frequency (RF) output connection and/or with an integral antenna; • for alarms, identification, telecommand, telemetry, etc., applications; • with or without speech. • It covers fixed stations, mobile stations and portable stations, all types of modulation. June 14

  25. The EMC certification Case study 2 • List of suggested tests: • Some ESD tests should be also done … June 14

  26. The EMC certification Case study 3 • You are a semiconductor manufacturers and you want to sell your integrated circuits in the European market. Your ICs are dedicated to automotive applications. • Which EMC standard(s) should you follow ? What tests should you conduct for the EMC certification ? June 14

  27. The EMC certification Case study 3 • If your integrated circuits can not operate by themselves, you don’t need EMC certification. • However, your customers will certainly push you to guarantee the low emission and susceptibility of your devices, require measurements, models, support…. • Examples of standards providing EMC measurement for ICs: • IEC 61967: Integrated Circuits, Measurement of Electromagnetic Emissions, 150 kHz to 1 GHz • IEC 62132: Integrated circuits - Measurement of electromagnetic immunity, 150 kHz to 1 GHz • ISO11452: Road vehicles - Electrical disturbances by narrowband electromagnetic energy - Component test methods • ISO 7637 or IEC61000-4-2/4/5 for ESD, pulse, surge testing. June 14

  28. EMC measurement for electronic systems Why EMC standard measurement methods • Check EMC compliance of ICs, equipments and systems • Comparison of EMC performances between different products, different technologies, designs, PCB routings • Improve interaction between customers and providers (same protocols, same set-up) June 14

  29. EMC measurement for electronic systems Control - Acquisition Radiated or conducted coupling Acquisition system 50Ω adapted path Coupling device • Spectrum analyzer • EMI receiver • Oscilloscope • Coupling network • Antennas • Wave guide • Current clamp… Emission requirements verified ? Emission measurements – General measurement set-up Equipment / Device under test June 14

  30. EMC measurement for electronic systems Emission measurements – Emission spectrum Amplitude (dBµV) Frequency (MHz) June 14

  31. EMC measurement for electronic systems Emblematic EMC equipment – Spectrum Analyzer (EMI receiver) Frequency adjustment : Start, stop , center Y= power (dBm, dBµV) RBW – frequency resolution, noise floor reduction 50 Ohm input X= frequency VBW – smooth display • Emission measurement requires high sensitivity and resolution • Emission measurement standards often recommend spectrum analyzer adjustment Amplitude adjustment : Level reference, dynamic. June 14

  32. EMC measurement for electronic systems Emblematic EMC equipment – Spectrum Analyzer (EMI receiver) • Principle: based on super heterodyne receiver Input signal Output signal IN Mixer OUT IF filter f Frf Local oscillator LO f Fif Frf+Flo f Flo OUT ωif IF filter A Detected power: RBW P = ½.A²+No.RBW No f Fif June 14

  33. EMC measurement for electronic systems Gain IF Emblematic EMC equipment – Spectrum Analyzer (EMI receiver) • Building blocks and adjustable elements: Detector Attenuation Input signal RBW Envelope detector VBW Mixers IF filter Analog filter Attenuator DC blocking Gain log Video filter Low pass filter Local oscillator Display Frequency sweep Reference oscillator Fstart / Fstop Fcenter / Span Point number June 14

  34. EMC measurement for electronic systems Emblematic EMC equipment – Spectrum Analyzer (EMI receiver) • Example: effect of RBW and VBW. • Measurement of 100 MHz sinus. Amplitude = 90 dBµV Amplitude = 20 dBµV Sweep time : VBW = 30 KHz  100 ms VBW = 1 KHz  980 ms Sweep time : RBW = 100 KHz  2.5 ms RBW = 10 KHz  100 ms June 14

  35. EMC measurement for electronic systems Emblematic EMC equipment – Spectrum Analyzer (EMI receiver) • Example: Influence of detector type (peak vs. quasi-peak vs. average). • Measurement of radiated emission of a microcontroller. June 14

  36. EMC measurement for electronic systems Radiated emission in (semi-)Anechoic chamber (30 MHz – 1 GHz) EN55022 (Siepel) Absorbents Faraday cage (with absorbents: semi-anechoic chamber) Wide band (calibrated) antenna Device under test 1 m 1 m EMI receiver or spectrum analyzer) R = 3 ou 10 m 1 m Power supply, DUT control June 14

  37. EMC measurement for electronic systems Radiated emission in (semi-)Anechoic chamber (30 MHz – 1 GHz) If far field and free space conditions ensured: Optional pre-amplifier Low loss 50 Ω cable EMI receiver 50 Ω E field Vemi Bilog antenna (or log-periodic, biconical, dipole…) AF = Antenna factor (from calibration) The E field varies in 1/r with the distance r (the radiated power in 1/r²)  possible extrapolation of field intensity. 37 June 14

  38. EMC measurement for electronic systems Radiated emission in (semi-)Anechoic chamber (30 MHz – 1 GHz) Let’s consider a radio receiver (such as a mobile phone). We suppose that it operates at 900 MHz, its antenna has an antenna factor of 29 dB/m, and its receiving floor is -90 dBm. It is placed at 1 m of a “noisy” electronic equipment with a CE Mark. Could you have a risk of interferences ? 38 June 14

  39. EMC measurement for electronic systems Failure detection Injected level Extraction Disturbance generation Radiated or conducted coupling 50Ω adapted path Coupling device • Coupling network • Antennas • Wave guide • Clamp… • Harmonic signal • Transients • Burst Immunity requirements verified ? Immunity measurements – General measurement set-up Equipment / Device under test June 14

  40. EMC measurement for electronic systems Start End Immunity measurements – General test procedure for harmonic disturbance F = Fmin P = Pmin Increase P Detection mask Without EMI Increase F Wait dwell time Failure or P = Pmax ? Save F and P F = Fmax ? With EMI Failure June 14

  41. EMC measurement for electronic systems Radiated immunity in (semi-)Anechoic chamber (30 MHz – 1 GHz) Typical max. RI level: Commercial product: 3 – 10 V/m Automotive (ISO-11452-2): 25 – 200 V/m Military (MIL-STD461E): 20 – 200 V/m Aeronautics (DO160-D): 8 – 800 V/m (Siepel) Field monitoring Absorbents Signal synthesizer Wide band (calibrated) antenna Device under test Faraday cage (with absorbents: semi-anechoic chamber) 1 m 1 m R = 3 ou 10 m Power amplifier ( > 100 W) 1 m Power supply, DUT control June 14

  42. EMC measurement for electronic systems DUT Immunity measurements – Bulk current injection (BCI) Signal synthesizer RF disturbance Induced current measurement Power amplifier Induced RF current Directional coupler Failure ? LoadLISN Bus, cable Interface circuit Microcontroler Measurement clamp Injection clamp Faraday cage • Usually, the max. current is between 50 mA and 300 mA. June 14

  43. EMC measurement for electronic systems Immunity measurements – Pulse, ESD, bursts, surge… • Pulse waveforms and severity levels defined by standards such as IEC61000-4-x or ISO7637 Ideal Fast transient / burst (IEC61000-4-4) (level 2) Ideal ESD waveform at 4 KV (IEC61000-4-2) (level 2) Ipeak = 15 A Vpeak = 1 KV (on 50 Ω) Td= 50 ns Tr = 5 ns Repetition rate = 5 – 100 KHz I30 = 8 A Vpeak = 1 KV (on 50 Ω) I60 = 4 A Tr = 0.8 ns June 14

  44. EMC measurement for integrated circuits Why testing EMC for ICs ? • Integrated circuits are often the main cause of disturbances in electronic equipment. • In recent years, there has been a strong demand for simple, reliable and standardized measurement methods focusing only on integrated circuits that electronic system designers could use to: • Obtain quantitative measure of emission/immunity from ICs establishing a uniform testing environment • Qualify the low emission and high immunity performance of circuit. • Optimize circuit placement, routing, filtering and decoupling components • Evaluate the impact of IC redesign, technology improvement or package modification. June 14

  45. EMC measurement for integrated circuits Why testing EMC for ICs ? • Based on pre existing standards, such as: • CISPR 25 – Radio disturbance characteristics for the protection of receivers used on board vehicles, boats and on devices – Limits and methods of measurements • IEC 61000-4 – Electromagnetic Compatibility (EMC) – Part 4: Testing and measurement techniques • ISO 11452 part 1 to 7, Road vehicles – Electrical disturbances by narrow band radiated electromagnetic energy – Component test methods • Measurement methods for EMC of Ics proposed by IEC: • IEC 61967:Integrated circuits -Measurement of electromagnetic emissions, 150 kHz to 1 GHz. • IEC 62132: Integrated circuits - Measurement of electromagnetic immunity, 150 kHz to 1 GHz. • IEC 62215: Integrated circuits – Measurement of impulse immunity June 14

  46. EMC measurement for integrated circuits Conducted method Radiated method TEM Cell improvemnt Investigation method International standards for IC emission measurement methods June 14

  47. EMC measurement for integrated circuits Icore(t) VE/S(t) Iosc(t) Vdriver(t) IC Conducted emission VddCore Integrated circuit Digital Core Vdd osc I/O Load Oscillator Driver PCB line Load • Two noise sources: internalactivity (power supply noise) and I/O switching (SimultaneousSwitching Noise, I/O line excitation) • Characterization of transientcurrent and voltage induced by ICs. June 14

  48. EMC measurement for integrated circuits RF current 49 Ω Spectrum analyzer 1 Ω IC Conducted emission - IEC 61967-4 –1 ohm / 150 ohms method • Conducted emission is produced by RF current induced by IC activity. • The current induced voltage bounces along power distribution network and radiated emission. Vdd PCB IC Decoupling « Local » ground IRF « Global » ground The  « 1 ohm » method aims at measuring the RF current flowing from circuit Vss pin(s) to the ground reference. June 14

  49. EMC measurement for integrated circuits 150 Ω matching network RF current 6.8 nF 120 Ω Spectrum analyzer 51 Ω VRF VA RF current IC Conducted emission - IEC 61967-4 –1 ohm / 150 ohms method • I/O switching is a major contributor to conducted emission. • They induced voltage fluctuation along power supply and I/O lines. Vdd I/O buffer Decoupling External load PCB The « 150 ohms » method aims at measuring the RF voltage induced at one or several IC output. June 14

  50. EMC measurement for integrated circuits IC current extraction from 1 Ω probe measurement • dsPIC33F: measurement in time domain and frequency of the voltage across the 1 Ω probe  proportional to the IC current. June 14

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