Power-bus decoupling with embedded capacitance in printed circuit board design |
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Authors: | Minjia Xu Hubing TH Chen J Van Doren TP Drewniak JL DuBroff RE |
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Affiliation: | Hewlett-Packard, San Diego, CA, USA; |
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Abstract: | This paper experimentally investigates the effectiveness of embedded capacitance for reducing power-bus noise in high-speed printed circuit board designs. Boards with embedded capacitance employ closely spaced power-return plane pairs separated by a thin layer of dielectric material. In this paper, test boards with four embedded capacitance materials are evaluated. Power-bus input impedance measurements and power-bus noise measurements are presented for boards with various dimensions and layer stack ups. Unlike discrete decoupling capacitors, whose effective frequency range is generally limited to a few hundred megahertz due to interconnect inductance, embedded capacitance was found to efficiently reduce power-bus noise over the entire frequency range evaluated (up to 5 GHz). |
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