Overview
IEC 61967-4:2021 - Integrated circuits - Measurement of electromagnetic emissions - Part 4: Measurement of conducted emissions - 1 ohm/150 ohm direct coupling method - defines a standardized laboratory method to measure conducted electromagnetic emissions (EME) from integrated circuits (ICs). The standard prescribes direct RF current measurement using a 1 Ω resistive probe and RF voltage measurement using a 150 Ω coupling network to ensure reproducible, comparable results between test labs and designers.
This edition (2021) introduces notable changes:
- the phrasing "150 kHz to 1 GHz" was removed from the title;
- the recommended frequency range for the 1 Ω method has been reduced to 30 MHz;
- Annex G adds guidance for extending measurements beyond 1 GHz.
Key topics and requirements
- Measurement principles: direct RF current injection and RF voltage coupling to characterize conducted emissions at IC pins and return paths.
- Test equipment and probes: specifications and verification procedures for the 1 Ω RF current probe, RF measuring instruments and the 150 Ω impedance matching network.
- Test setup and PCB considerations: recommended printed circuit test board layouts, connector/jumper arrangements and examples of EMC main/IC test boards (Annex E).
- Test procedure and reporting: step‑by‑step measurement methods, probe calibration checks (Annex A), and required test report content to support reproducibility.
- Assessment and classification: informative annexes provide emission level classification (Annex B) and example reference levels for specific sectors (Annex C - automotive).
- Special topics: common‑mode coupling network designs for differential ICs (Annex F) and guidelines for frequency range extension above 1 GHz (Annex G).
Practical applications and users
Who will use IEC 61967-4:2021:
- IC designers and EMC engineers validating on‑die and package-level conducted emissions early in development.
- Test laboratories and compliance houses seeking standardized, repeatable procedures for IC‑level EME measurements.
- Automotive semiconductor suppliers and system integrators using the standard’s reference levels and test board examples.
- R&D teams investigating sources of conducted disturbances and grounding/return‑path mitigation.
Benefits:
- Improved reproducibility and correlation of IC emission measurements across labs.
- Clear guidance for selecting probes, coupling networks and PCB layouts to reduce measurement variability.
- Practical annexes that accelerate adoption for automotive and high‑speed differential interfaces.
Related standards
- IEC 61000‑4‑6 (referenced matching network concepts) and other IEC IC/EMC measurement standards can be used in conjunction with IEC 61967‑4:2021 for broader immunity and emission testing programs.
Keywords: IEC 61967-4:2021, integrated circuits, conducted emissions, electromagnetic emissions, 1 ohm probe, 150 ohm coupling, RF current measurement, EMC testing, probe calibration, high-frequency extension.