A low-cost technique for reducing the simultaneous switching noise in sub-board packaging configurations

As an easy-to-maintain low-cost packaging system, a sub-board packaging configuration has been developed. However, the simultaneous switching noise tends to increase, because a large number of switching large scale integrations (LSI´s) are integrated in a sub-board. A low-cost technique for reducing simultaneous switching noise in sub-boards has been developed. A thin insulator film made of conventional FR4 substrate material is used to reduce the frequency response in the power-supply planes of the sub-board at frequencies below about 600 MHz. The Vtt peak-noise amplitude was reduced by about 50% when 32 switching gates in the sub-board were simultaneously driven at 622.08 Mb/s.