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EMC measurements of electronic components

EMC measurements of electronic components. Summary. Context - EMC certification Illustration of electromagnetic emission produced by electronic devices Illustration of susceptibility to electromagnetic disturbances of electronic devices Some EMC measurement tests Conclusion. January 20.

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EMC measurements of electronic components

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  1. EMC measurements of electronic components

  2. Summary Context - EMC certification Illustration of electromagnetic emission produced by electronic devices Illustration of susceptibility to electromagnetic disturbances of electronic devices Some EMC measurement tests Conclusion January 20

  3. Context - The EMC certification European Directives for electronic products • RTT&E 1999/5/CE : for radio equipments and telecommunication terminals • CEM 2004/108/CE : electromagnetic compatibility of electronic products • BT 2006/95/CE : electric safety for electronic products (0 to 1000 volt AC and 1500 DC) • RoHS 2011/65/UE : limitation of six hazardous substances (e.g. lead) • DEEE 2002/96/CE : management of electric and electronic equipment waste January 20

  4. Context - 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 January 20

  5. Context - 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 January 20

  6. Context - The EMC certification Outside European Union ? • United States Federal Communications Commission (FCC) • Canada: Industrie Canada (IC) • Japan : Voluntary Control Council for Interference by Information Technology Equipment (VCCI) • China : China Compulsory Product Certification (CCC) • Australia – New-Zeland : Australian Communications Authority (ACA) • Taïwan : Bureau of Standards, Metrology and Inspection (BSMI) and National Communications Commission (NCC) • Russia : GOST (State Committee for Quality Control and Standardization ... Regulatory approchs of EMC in every countries. Non harmonized regulation between countries, except if Mutual Recognition Agreements (MRA) exists. January 20

  7. Context - The EMC certification Role of EMC standards • Define terms, units, general conditions • Define measurement methods (equipments, configuration, set-up) • Propose calibration procedures • Give suggested/mandatory limits • Guidelines for test reports • Appropriate for all products ? For all environments ? For all operating configurations ? • Do standards change with time ? January 20

  8. Context - The EMC certification EMC normative bodies 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 January 20

  9. Context - The EMC certification Commercial harmonized standard (non exhaustive list !) January 20

  10. Context - The EMC certification Commercial harmonized standard (non exhaustive list !) • Automotive, military, aerospace and railway industries have developed their own EMC standards. January 20

  11. Context - The EMC certification Case study 1 • Are the following product subject to the EMC European directive ? • WiFi dongle (ISM band) • Server motherboard • Passive antenna passive for RFID application • Wireless audio headset January 20

  12. Context - The EMC certification Case study 2 • You want to place on the European market a notebook. • Are you under the European EMC directive 2004/108/EC ? • If yes, which EMC standard(s) should you follow ? What tests should you conduct for the EMC certification ? January 20

  13. Context - The EMC certification Case study 2 • Application of EN55022 : “Information technology equipment – Radio disturbance characteristics – Limits and methods of measurement” and EN55024 : «  Information technology equipment – Immunity characteristics – Limits and methods of measurement » : • Any equipment dedicated to processing, storage, display, control of data and telecommunication messages, equipped with one or more ports, and supplied under less than 600 V. • Except equipments or modules dedicated only to radio emission or reception. January 20

  14. Context - The EMC certification Case study 2 • Suggested emission tests: • Suggested immunity tests: January 20

  15. Context - 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 ? January 20

  16. Context - 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. January 20

  17. EMC measurements of components Illustration of electromagnetic emission produced by electronic devices January 20

  18. Electromagnetic emission of electronic devices Emblematic EMC equipment – Spectrum Analyser (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 analyser adjustment Amplitude adjustment : Level reference, dynamic. January 20

  19. Electromagnetic emission of electronic devices Emblematic EMC equipment – Spectrum Analyser (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 January 20

  20. Electromagnetic emission of electronic devices Gain IF Emblematic EMC equipment – Spectrum Analyser (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 January 20

  21. Electromagnetic emission of electronic devices Emblematic EMC equipment – Spectrum Analyser (EMI receiver) • What are the main adjustments ? • What are their effects on measurement result ?

  22. Electromagnetic emission of electronic devices Emblematic EMC equipment – Spectrum Analyser (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 January 20

  23. Electromagnetic emission of electronic devices Emblematic EMC equipment – Spectrum Analyser (EMI receiver) • Example: Influence of detector type (peak vs. quasi-peak vs. average). • Measurement of radiated emission of a microcontroller. January 20

  24. Electromagnetic emission of electronic devices Case study 4 – Electromagnetic emission from a class-D amplifier • MAX9768 – 10 W mono class D speaker amplifier, EN55022 class B compliant. • Applications: low power portable application (notebook computer, Multimedia monitor, GPS navigation system…) www.maxim.com January 20 January 20

  25. Electromagnetic emission of electronic devices Case study 4 – Electromagnetic emission from a class-D amplifier • Class D amplifier principle (half-bridge): Amplified audio signal VDD Triangle waveform oscillator PWM signal Output filter + - Speaker Audio source GND GND January 20

  26. Electromagnetic emission of electronic devices Case study 4 – Electromagnetic emission from a class-D amplifier • Measure and compare the currents circulating on wires OUT+ and OUT- of the speaker cable. • Are they perfectly symmetrical ? GND I+ 8 ΩSpeaker Class D GND I- GND January 20

  27. Electromagnetic emission of electronic devices Case study 4 – Electromagnetic emission from a class-D amplifier • Differential vs. common mode currents. • Common mode appears when the return current path is not perfectly defined. If I1 ≠ I2 I1 Interco 1 Id Differential mode I2 Id 1 Decomposition in 2 distinct propagation modes Interco 2 2 Ic 1 Ic Common mode 2 January 20

  28. Electromagnetic emission of electronic devices Case study 4 – Electromagnetic emission from a class-D amplifier • Differential vs. common mode radiation (at a distance r in far-field). I1 d I2 L=1 m, d=2 mm, r = 3 m, IDM = 20 mA, ICM = 200 µA L << λ Evaluate radiation produced by the cable output of the class-D amplifier. January 20

  29. Electromagnetic emission of electronic devices Case study 4 – Electromagnetic emission from a class-D amplifier • Evaluate the differential and common-mode radiation at 3 m produced by the speaker cable. • Does it comply with EN55022 class B standard ? January 20

  30. Electromagnetic emission of electronic devices Icore(t) Iosc(t) Case study 5 – Electromagnetic emission from a microcontroller • Transient current produced by IC activity leads to conducted and radiated emission. VddDig IMem(t) Digital Core Memory Vdd IO Integrated circuit I/O Vddosc Analog Oscillator PLL IIO(t) Ext. Loads PCB lines IIO(t) IA(t) Vdd A January 20

  31. Electromagnetic emission of electronic devices z y x Case study 5 – Electromagnetic emission from a microcontroller • Magnetic field around a wire: Tangential probe Vmeas H Hy Vertical probe Scan axis y Vmeas Hz I • Link between the magnetic field and probe voltage: y January 20

  32. Electromagnetic emission of electronic devices Case study 5 – Electromagnetic emission from a microcontroller • The microcontroller Freescale MPC5604B has the following configuration: • CPU running at 40 MHz • Internal clock produced by an on-chip PLL running at 80 MHz, synchronized by a 8 MHz quartz oscillator • 13 I/O switching at 200 kHz • With a near-field probe, locate the main source of electromagnetic emission created by the microcontroller. • Do they really contribute to far-field radiated emission? January 20

  33. Electromagnetic emission of electronic devices Case study 5 – Electromagnetic emission from a microcontroller • Pin-out of microcontroller Freescale MPC5604B: VDDHV/VSSHV (I/O supply) VDDHV_ADC/VSSHV_ADC (ADC supply) 5 I/O switching at 200 kHz VDDLV/VSSLV (Core + PLL supply) 8 I/O switching at 200 kHz External quartz January 20

  34. Electromagnetic emission of electronic devices Case study 5 – Electromagnetic emission from a microcontroller • Near-field vs. far-field emission January 20

  35. Electromagnetic emission of electronic devices Case study 6 – Radiated emission from a digital line • Simple radiated emission model for a PCB microstrip line: Magnetic-field emission in near-field Worst-case electromagnetic emission in far-field: January 20

  36. Electromagnetic emission of electronic devices Case study 6 – Radiated emission from a digital line • Consider the following PCB digital line between two CMOS inverters: Magnetic-field probe (Loop radius = 2 mm) Inverter AHCT04 Inverter AHCT04 Microstrip line (w = 1 mm, h = 1.6 mm, L = 10 cm) 10 MHz • At three different frequency between 10 and 1000 MHz, estimate the current which circulated along the microstrip line. • Estimate the far-field emission at 3 meter. • Does the radiated emission comply with EN55022 limit? January 20

  37. EMC measurements of components Illustration of susceptibility to electromagnetic disturbances (RFI) of electronic devices January 20

  38. Susceptibility of electronic devices to RFI Effect of IC malfunction due to EM disturbance • Striking of berth by Coastal Inspiration, 20th dec 2011, Nanaimo, British Columbia, Canada. • A problem of an amplifier, due to EM disturbances, leads to a failure in speed reduction command. January 20

  39. Susceptibility of electronic devices to RFI Case study 7 – Susceptibility of a bandgap reference voltage • LTC1798: 2.5 V micropower bandgap voltage reference Effect on the output voltage ? RFI 2.7 V to 12 V 2.5 V +/- 4 mV LTC1798 100 nF 100 nF • Couple an harmonic conducted disturbance to the input of the bandgap reference. • Observe the effect on the output voltage, for frequencies ranging from 1 to 100 MHz. January 20

  40. EMC measurements of components Some EMC measurement tests January 20

  41. Emission measurement set-up Control - Acquisition Radiated or conducted coupling Result de-embedding Post-processing Acquisition system 50Ω adapted cable Coupling device • Spectrum analyser • EMI receiver • Coupling network • Antennas • Waveguide Emission – General measurement set-up Device under test January 20

  42. Emission measurement set-up Typical conducted emission test for electronic/electrical products • Frequency range = 150 kHz – 30/150 MHz Line Impedance Stabilized Network(LISN) EMI receiver Current clamp Power supply harness EUT Load harness Load Ground plane January 20

  43. Emission measurement set-up Typical conducted emission test for electronic/electrical products • Conducted emission test with Line Impedance Stabilizer Network (LISN)

  44. Emission measurement set-up Typical radiated emission test for electronic/electrical products • Frequency range = 30 MHz/80 MHz – 1 GHz and more EN55022 (Siepel) Absorbents ALSE = 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

  45. Emission measurement set-up Typical radiated emission test for electronic/electrical products If far field and free space conditions ensured: Optional pre-amplifier Low loss 50 Ω cable EMI receiver Rs =50 Ω E field Vemi Voltage Vemi or Power Pemi 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. 45 January 20

  46. Emission measurement set-up 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. The  « 1 ohm » method aims at measuring the RF current flowing from circuit Vss pin(s) to the ground reference. January 20

  47. Emission measurement set-up IC Conducted emission - IEC 61967-4 –1 ohm / 150 ohms method • dsPIC33F: measurement in time domain and frequency of the voltage across the 1 Ω probe  proportional to the IC current. January 20

  48. Emission measurement set-up 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. The « 150 ohms » method aims at measuring the RF voltage induced at one or several IC output. January 20

  49. Susceptibility measurement set-up Injected level Extraction Disturbance generation Radiated or conducted coupling Result de-embedding Port-processing 50Ω adapted cable Coupling device • Coupling network • Antennas • Waveguide • Harmonic signal • Transients • Burst Susceptibility measurements – General measurement set-up Device under test January 20

  50. Susceptibility measurement set-up Susceptibility measurements – General measurement set-up • Typical signals for susceptibility tests: January 20

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