Patent ID: 8085548
Filing Date: 2011-12-27
Classification: H05K

Abstract:
1. A circuit substrate comprising: a power supply layer; a GND layer; an opening for inserting a connecting part for connecting the circuit substrate and a cabinet; a GND conductor pattern provided in a circular shape on a circumferential edge of the opening to connect to a cabinet GND through said connecting part when said connecting part is inserted into the opening, and electrically connected to the substrate GND through a through hole and said the GND layer; a power supply conductor pattern placed near said GND conductor pattern and electrically connected to a power supply of the circuit substrate through a through hole and said the power supply layer; an impedance part comprising at least one capacitor directly connected to said a GND conductor pattern, and connected to said GND conductor pattern and said a power supply conductor pattern: wherein said impedance part is implemented with connecting to said GND conductor pattern which is placed at the circumferential edge of the opening and said power supply conductor pattern at a distance of ¼ *f*tpd or less from a center of said the opening for inserting a connecting part for connecting the circuit substrate and the cabinet on the circuit substrate where the caused noise voltage is f, and the propagation delay time is tpd, wherein said GND conductor pattern, said power supply conductor pattern and said impedance part are placed on one side of said circuit substrate; wherein said a GND layer is formed in said a circuit substrate or on an opposite side to said one side of said circuit substrate, wherein said power supply layer is formed in said circuit substrate or on the opposite side of said circuit substrate, and wherein only said GND conductor pattern is implemented between said opening and said circuit substrate.