Impedance analysis on power distribution lines in multi-layer printed wiring board

摘要

To research the relationship between a board resonance and an effect of an additional inductance to the power lines in a module on PWB, we constructed a real-board and made measurements of its radiated emissions. In addition, impedance for elements of the board was measured and is related to its emissions. As a conclusion, for a board with a power-plane structure, the method of an additional inductance is much influenced by the effect of a loop resonance which includes a path through a decoupling capacitor. Each impedance of elements in a board can be a characteristic to evaluate the effect of an additional inductance.