An Active Magnetic Probe Array for the Multiple-Point Concurrent Measurement of Electromagnetic Emissions

In order to diagnose the EMI (Electromagnetic Interference) problem of ICs, an integrated active magnetic probe array has been developed in SOI (Silicon On Insulator)-CMOS technology. Three aligned differential coils, differential amplifiers, a differential to single-ended converter, an output buffer and bias circuits are all integrated in a single-chip. A measurement result shows that the probe achieves an e-field suppression ratio of 33.6 dB at 50 MHz. Furthermore, a two-dimensional magnetic field distribution map is drawn by the probe array using the 3-point concurrent measurement. The obtained image gains three times higher resolution than that of a single scan under an identical condition