A simulation study of simultaneous switching noise

This paper describes a new methodology for simultaneous switching noise (SSN) simulations by using a system level signal integrity (SI) analysis software, which is combinations of a quick full wave electromagnetic field solver for multiple-layer structure based on FDTD (Finite Difference Time Domain) and a circuit solver. The solution is based on the geometry, material, stack-up structure, and basic circuit information. The simultaneous switching noise issue is studied for two types of chipset packages-OLGA (Organic Land Grid Array) and WBGA (Wirebond Ball Grid Array)-with 40 drivers switching simultaneously. Different simulation conditions, such as with or without on-die interconnection model, different on-die decoupling capacitor values, are imposed during the simulations. Simultaneous switching noise (SSN) effects such as skew, signal overshoot, ring back, and power-ground voltage fluctuations, are obtained and compared. These data can be used for a design guideline specification or for package performance improvement purposes. It is believed that all these studies are very informative to chip and package analysis and design for high-speed system applications.