Patent ID: 8174843

Claim:
A printed circuit board comprising: a semiconductor integrated circuit having a power source terminal and a ground terminal; and a printed wiring board on a surface of which the semiconductor integrated circuit is mounted, the printed wiring board having on the surface a power source pattern connected to the power source terminal and a ground pattern connected to the ground terminal and a conductor pattern, wherein the printed wiring board includes a plane conductor that does not establish direct current continuity with the power source pattern and the ground pattern, wherein the power source pattern is connected to the conductor pattern through a first capacitor, the ground pattern is connected to the conductor pattern through a second capacitor, and the conductor pattern is connected to the plane conductor through a first filter, and wherein the printed wiring board is a multilayer board and includes a ground layer, a power source layer, and a wiring layer in which the plane conductor is formed, and wherein the plane conductor is connected to one of the ground layer and the power source layer through a second filter.