SDAA522 September   2026 ISO6020 , ISOM8110 , ISOM8110-Q1 , ISOM8113-Q1 , ISOM8610 , ISOM8710 , ISOW6441

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1 Introduction
    1. 1.1 Why Magnetic Field Immunity Matters for Isolators
  5. 2 Magnetic Field Units at a Glance
  6. 3 IEC 61000-4-8 — Power Frequency Magnetic Field Immunity
    1. 3.1 What IEC 61000-4-8 Test Simulates
    2. 3.2 Test Levels for IEC 61000-4-8 Continuous Power Frequency Fields
    3. 3.3 Environment Classes — How a Level is Chosen
    4. 3.4 Field Strengths Observed in Actual Installations
  7. 4 IEC 61000-4-9 — Pulse Magnetic Field Immunity
    1. 4.1 What IEC 61000-4-9 Test Simulates
    2. 4.2 Impulse Current Waveform for Pulse Magnetic Field
    3. 4.3 Test Levels for IEC 61000-4-9 Pulse Magnetic Fields
  8. 5 Summary of Class 5 Testing— What We Are Targeting
  9. 6 What "PASS" Means — Performance Criteria
  10. 7 Test Setup Details
  11. 8 Test Results and Summary
    1. 8.1 Test Conditions for Both Standards:
  12. 9 System Design Considerations for End Equipment Performance
  13. 10Summary
  14. 11References

Abstract

Isolation devices operate at the boundary between a noisy, high-power domain and a quiet, low-voltage control domain. That boundary is typically a few centimeters from a bus bar, a motor winding, a transformer, or a switching device — all of which generate strong magnetic fields. If those fields couple into an isolator which is not robust enough, the result can be a corrupted data bit, a false gate-driver edge, or a corrupted measurement.

This application note explains, in plain language, the two IEC standards that define how magnetic field immunity is tested: IEC 61000-4-8 (power-frequency fields) and IEC 61000-4-9 (pulse fields). This document also explains what the test levels and environment classes mean and how TI's isolation devices (Table 8-1) perform against the highest severity level defined by both standards, Class 5 .