1. aei_emc-1 EMC basics Centro Studi e Laboratori Telecomunicazioni S.p.A. - Torino (Italy) Flavio Maggioni

2. aei_emc-2 Design Prototype ProductionField Time Cost of solution Design phase EMC problem solving techniques EMC cost in a Product

3. aei_emc-3 EMC radiated Two origins: Differential mode Common mode Ground Dispersion impedance Radiation field = f(I, area loop) Idiff Icm Common mode currents are more dangerous than differential mode currents Idiff = hundreds of mA Icm = few uA but large area

4. aei_emc-4 EMC problems Emission Susceptibility Radiated Conducted Radiated Conducted ESD Fast Transient Lightening

5. aei_emc-5 Noise on PCBs ground plane Components drivers generate currents on ground/power planes Low impedance planes No-low impedance planes Cable shield connected to ground plane Low common mode radiation High common mode radiation Important: guarantee low impedance on ground planes

6. aei_emc-6 Radiated emissions Mainly due: to clocks (all frequencies) cables (low frequencies

7. aei_emc-7 Laboratory activity Manufacturer Test defined by standards Conformity declaration EMC laboratory

8. aei_emc-8 Test laboratory mission Accurate Repeatable Reproducible Accurate Repeatable Reproducible Accurate Test Environment Test results must be

9. aei_emc-9 Testinginstruments Test specifications and procedures Test environment Personale di Lab. Calibration StandardsStandards EMC Laboratory EMC Laboratory Components

10. aei_emc-10 Main causes of EMC problems Low frequency conducted noise –harmonics –Power supply variations –Power down or power supply glitches –Power supply frequency variations –Low frequency inductive voltage noise Low frequency radiated emissions – magnetic field –electrical field High frequency conducted noise –inducted voltage and currents –lightening –fast transient High frequency radiated emissions –EMC from board, cables and apparatus Electrostatic discharge (ESD)

11. aei_emc-11 EMC cause - effect relationship Noise degradation Malfunctions Loss of functionality Noise sources Radiate noise Low frequency magnetic fields Conducted noise, Fast transient ESD DUT Coupling mechanism Visible effect Signal lines TLC lines space AC supply DC supply

12. aei_emc-12 Test instruments Must satisfy standards requirements Must be calibrated and periodically verified (see Standards) Calibration instruments must be identifiable There are standards for the calibration report  Example of instruments requiring calibration: - EMI receiver - Antennas - GTEM - Field probes - LISN, Coupling networks, current probes, etc.

13. aei_emc-13 Testing sites Radiate emission Sito di misura all’aperto (Open Area Test Site OATS) Camera Schernata Semianecoica (CSSA) Radiated and conducted susceptibility Anechoic chambers Shielded chambers TEM e GTEM cells

14. aei_emc-14 Example of testing environment for conducted and radiated emission EUT EMIRECEIVER RF in IEEE 488 BUS MAST CONTROLLER TURN TABLE CONTROLLER LISNEUT SYSTEM CONTROLLER PRINTER a b SHIELDED CHAMBER POWER SUPPLY

15. aei_emc-15 LINE IMPEDANCE STABILIZATION NETWORKS (LISN): fixes the measuring impedance and filters noise not generated by the EUT TO EUT FREQUENCY (MHz) IMPEDANCE FREQUENCY CHARACTERISTIC OF LISN (10 kHz-30 MHz).01.1110 20 30 40 50 60 I M P E D A N C E (Ohms) TO POWER SOURCE 50  H 1000 .1  F 1F1F EMI RECEIVER (50  )

16. aei_emc-16 Radiated Emission: Site attenuation ANSI C63.4, 1992 and CISPR 16-1 Radiated Emission: Site attenuation ANSI C63.4, 1992 and CISPR 16-1. == Shielded chamber A t A r D h t h r Anechoic material Signal generator EMI Receiver h t = 1, 2 m. hr = 1 - 4 m.

17. aei_emc-17 Radiated immunity testing site Uniform field area 0,8 m Anechoic material to reduce floor reflections (only between EUT and antenna) Note:The anechoic material is everywhere 3 m Technical passage for cables No-conductive support 80 cm high. Power supply filter Transmitting antenna Interconnection filters Field source generator and amplifiers Auxiliary equipments

18. aei_emc-18 Set-up for radiation immunity Pwer amplifier GPIB GTEM Field probe Field monitor EUT RF generator

19. aei_emc-19 Conducted Immunity SET-UP 10 cm Ground plane AUX. EQUIPMENT 1 CDN EQUIPMENT UNDER TEST CDN AUX. EQUIPMENT 2 T T2 GENERATORE RF Signal generator T = 50  LOAD, T2 = POWER ATTENUATOR (6 dB), CDN = COUPLING AND DECOUPLING NETWORK