With the growing concerns about safety of electronic equipment in complex electromagnetic environments, the characterization and prediction of integrated circuits (ICs) susceptibility to multitone disturbance become more and more urgent. This paper proposes an efficient method to characterize the response of an IC to multitone disturbance, based on a conventional continuous wave (CW) susceptibility test followed by a large-band injection test. The proposed test aims at verifying the application of the disturbance superposition principle of an IC terminal. If it applies, the risk of failure due to any combination of harmonic disturbances can be determined from the usual CW susceptibility test results. The only difference is that the RF synthesizer is replaced by an Arbitrary Waveform Generator in order to produce a comb signal composed of several equidistant harmonics with equal amplitude.

The paper presents the approach, the proposed indicators to test the disturbance superposition principle assessment and the validation results of the method applied to six different ICs, presenting different functions and technologies (op-amp, bandgap reference, DC-DC converter, digital gates, microcontroller I/O). In spite of the non-linear reaction of the tested IC to electromagnetic disturbance, the results show that the disturbance superposition principle applies as long as one failure mechanism is activated. The validation of this principle on an IC simplifies substantially the EMC risk assessment when the IC is exposed to a complex combination of harmonic disturbances, as demonstrated by the experimental results presented in this paper.