PURPOSE: A double-layered printed circuit board is provided to reduce simultaneous switching noises by simplifying power traces which is formed in the printed circuit board. CONSTITUTION: A ground plane(2) is stacked on the entire of a first substrate. The first substrate includes a decoupling capacitor(4). A second substrate includes a power plane(5) which transmits power by being stacked on a component position. The second substrate includes a signal trace and a power trace in order to transmit signal and power to a component. The power pins of the component which is mounted on the second substrate is connected through the decoupling capacitor and a via.
