Interferences of Electromagnetic Pulses on Microcontroller Units

In this study, electromagnetic interference testing of microcontroller units (MCUs) under different electromagnetic pulse (EMP) amplitudes, full width at half maximum (FWHM), and at different angles was carried out on an EMP cell. The coupling path of the radiation-type EMP experiment on the circuit board is random. However, in several experiments with two pins specific to a certain integrated circuit, by measuring the interference voltage of MCU pins, the statistical results indicate that as the pressure of the air gap switch of the power source increased, both the breakdown voltage and the electric field in the transverse electromagnetic (TEM) cell increased, resulting in higher electromagnetic interference (EMI) received by these two pins. As the capacitance of the storage capacitor increased, the EMI also increased. In addition, the results showed that the interference of EMP on the MCU had strong directionality; i.e., path selectivity, which was related to the structure of the MCU. X-ray imaging of the destroyed MCU showed that when the internal wiring direction of the pin is consistent with the propagation direction of the interference pulse, the EMI was minimal or even unnoticeable.