Analysis of chip-to-chip power noise coupling on several SDRAM modules

This paper illustrates the noise characteristics under chip´s operations according to types of packages and modules for DDR SDRAM. The impedance profiles and power noises are analyzed with SDRAM chips having TSOP package and FBGA package on TSOP-based DIMM and FBGA-based DIMM. In controversy with common concepts, the noise characteristics of FBGA package are more weak and sensitive than those of the TSOP package. In addition, the simulated results show that the decoupling capacitor locations of modules are more important to control the self and transfer noise characteristics than the lead inductance of the packages. Therefore, satisfying the target spec of the noise suppression and isolation can be achieved through the design of power distribution systems only with considering not only the package types but also the whole module system.