Non-Invasive IC RF Immunity Assessment Using Magnetic Field Injection Probe

Accurate evaluation of the radio-frequency (RF) immunity threshold of integrated circuits in complex electromagnetic environments is essential. Compared with the conventional direct power injection (DPI) method, the magnetic field injection probe (MFiP) enables non-intrusive measurement. This paper investigates the coupling model between the magnetic field probe and the PCB transmission line, analyzing the correlation between the induced voltage and the magnetic field strength. A microprocessor supervisory circuit chip is used as the device under test to validate the application of the MFiP in chip-level RF immunity testing. By utilizing the calibration factor and field distribution of the MFiP, a relationship between the immunity threshold and the injected signal voltage is established and compared with the traditional DPI method. Results demonstrate that the MFiP can reproduce the same susceptibility phenomena as the DPI method while also obtaining frequency-dependent immunity thresholds, showing its potential as a non-destructive alternative to DPI.