Modeling The Conducted Electromagnetic Immunity Of A Microcontroller

To promote the modeling standardization process of the integrated circuits, an improved simulation model for a Direct Power Injection (DPI) setup which was used to measure the conducted immunity of a 16-bit microcontroller to radio frequency aggression was investigated. Based on the existing model of the same microcontroller, the Passive Distribution Network (PDN) module was modified by adding the core, Phase-Lock-Loop (PLL) and A/D network models, which could reflect the actual electric distribution situation within the microcontroller more accurately. The parameters of the modified PDN were extracted from S matrixes. The effectivness of the modified PDN module in the electromagnetic emission field can be proved by comparing the measured and simulated results obtained from the 1Ω/150Ωmethod, Transverse Electromagnetic Mode (TEM) cell method and near field scan method. Linked this modified PDN module to the complete immunity model and compared the simulation results with the measurement results, the effectiveness of the modified model can be approved to 500MHz, and its uncertainty is within±1.8dB (±2dB is acceptable).Then, to improve the simulation accuracy of the complete model in the high frequency range, the second modified I/O model which considered the variation of the internal impedance of the microcontroller with the increasing frequency was introduced. By comparing the simulation results with the measurement results, the effectiveness of the second modified model can be approved up to 1.4GHz within±1.8dB uncertainty. Thus, a conclusion can be reached that the proposed model can be applied to a wider frequency range within a smaller uncertainty than that of the latest model of the same microcontroller. Furthermore, associated with the electromagnetic emission testing platform model, the PDN module can also be used to predict the electromagnetic conducted and radiated emission characteristics. This modeling method can also be applied to other integrated circuits, and this model can be directly used to the complete model of Printed Circuit Board (PCB) level, which is very helpful to the standardization of the IC electromagnetic compatibility modeling process.At last, some suggestions to improve the electromagnetic immunity characteristics of the microcontroler were provided to IC electromagnetic compatibility engineers as the design guides.