CISPR 22: EN 55022 EMC Standard

EN 55022 / CISPR 22 provide the information for information technology equipment, ITE for the radio disturbance characteristics for electromagnetic compatibility compliance.

EMC / EMI Includes:
EMC basics     EMI interference basics     EMC standards     CISPR11     CISPR16     CISPR22     FCC 47 part 15     EMC design techniques     EMC compliance test    

CISPR 22 is a widely used standard for electromagnetic compatibility within Europe for Information Technology Equipment, ITE. CISPR 22 is maintained by CISPR: the International Special Committee on Radio Interference

There is also another related standard: EN 55022 which is the CENELEC standard. EN 55022 is a modified derivative for CISPR 22 and as a result both standards are used within the industry.,

CENELEC is the European Committee for Electrotechnical Standardisation and has produced EN 55022 based upon the original CISPR 22 standard.

What is CISPR 22

CISPR 22 is the CISPR standard for Information Technology Equipment-Radio Disturbance Characteristics-Limits and Methods of Measurement.

CISPR 22 has been adopted for use by most members of the European Community.


With CISPR 22 being widely used within the European Community, it is often necessary to relate it to other standards, the main one being the FCC, Federal Communications Commission in the USA. Here the FCC Part 15 standard is used.

To ensure that either standard can be used to certify digital electronic equipment, FCC Part 15 and CISPR 22 have been made to be relatively harmonious, although there are a few differences.

CISPR 22 differentiates between Class A and Class B equipment and it gives figures for conducted and radiated emissions for each class. In addition, CISPR 22 requires certification over the frequency range of 0.15 MHz to 30 MHz for conducted emissions. On these points there are differences between CISPR 22 and the FCC Part 15.

Also CISPR 22 has no specified limits for frequencies above 1.0 GHz, and CISPR limits are provided in dBµV, while the FCC limits are specified in µV which means that a simple conversion is required for direct comparisons.

In terms of similarities the conducted and radiated emission limits specified in CISPR 22 and FCC Part 15 are close to each other, i.e. within a few dB of each other over the detailed frequencies.

In this way it is possible to meet both standards easily for the certification process.

Summary of CISPR 22 limits

The tables below give a summary of the field strength limits for conducted and radiated emissions within the per CISPR 22 standard.

CISPR 22 Class A Conducted EMI Limit
Frequency of Emission (MHz) Conducted Limit (dBµV)
  Quasi-peak Average
0.15 - 0.50 79 66
0.50 - 30.0 73 60

CISPR 22 Class B Conducted EMI Limit
Frequency of Emission (MHz) Conducted Limit (dBµ;V)
  Quasi-peak Average
0.15 - 0.50 66 to 56 56 to 46
0.50 - 5.00 56 46
5.00 - 30.0 60 50

CISPR 22 Class A 10-Metre Radiated EMI Limit
Frequency of Emission (MHz) Field Strength Limit (dBµV/m)
30 - 88 39
88 - 216 43.5
216 - 960 46.5
above 960 49.5

CISPR 22 Class B 3-Metre Radiated EMI Limit
Frequency of Emission (MHz) Field Strength Limit (dBµV/m)
30 - 88 40
88 - 216 43.5
216 - 960 46.0
above 960 54.0

More Analogue Circuits:
Op Amp basics     Op Amp circuits     Power supply circuits     Transistor design     Transistor Darlington     Transistor circuits     FET circuits    
    Return to Analogue Circuits menu . . .