During operation, Integrated Circuits (ICs) can emit undesired electromagnetic energy in two ways. One way is radiated emission (via air), and the second way is conducted emission (unwanted RF noise current flowing through connected PCB traces, wires, or cables). This emitted unwanted electromagnetic energy from an IC may interfere with the operation of/affect the nearby devices; this phenomenon is known as electromagnetic interference (EMI).

The measurement of radiated and conducted emissions can offer valuable information for enhancing an IC's functionality and EMC performance.

Understanding IEC 61967-5:

IEC 61967-5 is an EMC standard that deals with the measurement of conducted emissions from integrated circuits (ICs) by using the workbench Faraday cage method (WBFC). It is the 5th part of the IEC 61967 series. Currently, the first edition of this standard (IEC 61967-5:2003, published in 2003) is available and valid. The title of the standard is “Integrated circuits - Measurement of electromagnetic emissions, 150 kHz to 1 GHz - Part 5: Measurement of conducted emissions - Workbench Faraday Cage method”.

The IEC 61967-5 standard describes a method to measure the conducted electromagnetic emission of integrated circuits (ICs) either applied on the standardized test board or a final printed circuit board (PCB). This standard covers the frequency range of 150 KHz to 1 GHz. The document of this standard describes the measurement method or test procedure, test conditions, test equipment, test set-up, and test report details. Also, it gives guidance for the Workbench Faraday Cage measurement method. This part of  IEC 61967 applies to integrated circuits (ICs), which can perform “stand-alone” functions when applied on a physically small printed circuit board (PCB). 

Here, the measurement is conducted on a table with the use of a small Faraday cage. Hence, this method is known as the Workbench Faraday Cage method or the Workbench method. This method allows for EMC pre-compliance testing and optimizing and comparing ICs and/or PCB designs. 

The measurement method specified in the IEC 61967-5 standard has a high repeatability and a good relationship to the measured RF emission of final applications with the integrated circuits used. 

Figure 1: Test set up for measuring emission with the WBFC

Figure 1 shows the measurement test setup. PCB is placed in a small Faraday cage to limit the influence of the ambient noise on the test results. The PCB is connected with all functional connections, e.g., the power supply and auxiliary equipment. The PCB under test is fed through dedicated filters mounted on the cage's wall. A spectrum analyzer is used to measure the emission level.

Additional information on IEC 61967-5:2003: