Radiated EMI prediction and mechanism modeling from measured noise of microcontroller

Since many extremely susceptible components with low-voltage operation or high sensitivity may be affected from EMI noise and degrade their performance, the EMI phenomena from IC becomes an issue for semiconductor industrial, such as IC design, IC packaging, and manufacturing foundry. In order to achieve the intra-system electromagnetic compatibility for optimal circuit layout and component placement, the EMI characteristics from critical integrated circuit must be taken into account during system design stage. In this paper, we will use electromagnetic software to build the model of the IC radiation mechanism, and then compare the simulation result with the measured characteristics of the radiated EMI result. Following the IC-EMI measurement standard IEC 61967-2 (TEM cell method) and IEC 61967-3 (Surface scan method), three identical dies of microcontroller packed by LQFP technology with some minor modifications were used for investigation. To facilitate the testing board for measuring and analysing the radiated interference, we first utilized the TEM cell to identify the most significant noise frequencies and then performed the near field surface scan at those frequencies to find out the orientation and the location of the radiation mechanism of the most significant interference frequencies.