Electromagnetic interference (EMI) behavior of system in package ( SIP)

We first report the electromagnetic interference (EMI) behavior of a system in package (SIP), consisting of MCU, NAND flash memory, SDRAM and printed circuit board (PCB) substrate, in comparison to the discrete PCB with individual integrated circuits (IC) mounted on a system board. RF current scanning, transverse electromagnetic (TEM) cell and semi-anechoic chamber were used for characterization of the radiated emission. It is found that the distribution area and intensity of radiated emission for the SIP is far less complicated and two times smaller than those of the discrete PCB. The TEM cell method indicates that the SIP EMI characterization is approximately 6-15 dBuV lower in the entire frequency range compared to the discrete PCB. For the semi-anechoic chamber, radiated emission of the SIP is much lower than the discrete system, and the difference is a maximum 15 dBuV and 7 dBuV in the lower and higher frequency regions, respectively. The effects of the power net impedance and power bouncing noise has been taken into account in considering the EMI behavior. Overall, the SIP demonstrates better EMI behavior than the discrete system due primarily to reduction of the radiation source in size and of the interconnection length. Consequently, such reduction of radiated emission from the SIP is a clear benefit for EMI in the higher frequency region.