Optimal filter design to suppress simultaneous switching noise [SSN] and EMI on power network based on precise SMD ferrite bead model

Abstract

Nowadays, clock frequency and maximum power in high-speed digital system have increased and power network is needed to supply power to chip. Power network also includes inductance. Therefore, simultaneous switching noise (SSN) generated in a digital system due to rapid changes in voltage and current caused by many circuits switching at the same time becomes more serious. SSN also causes electromagnetic interference (EMI) on high-speed digital system. EMI results in malfunction in sensitive chips and other systems. There are several countermeasures to reduce SSN and EMI. Filtering is one solution among those countermeasures. However, vendor produced filters have a few limitations. In this paper, design method for ferrite bead filter used in power network is suggested and filter performance is demonstrated with thorough modeling. Filter performance can be predicted more accurately with proposed ferrite bead model.