Patent ID: 7943864

Claim:
A printed circuit board having an analog circuit and a digital circuit, comprising: a first metal layer and a second metal layer, one of the first metal layer and the second metal layer being a power layer and the other of the first metal layer and the second metal layer being a ground layer; a third metal layer, layer-built between the first metal layer and the second metal layer; a mushroom type structure including a first via connected to a metal plate, the metal plate being arranged in a space between circuit patterns of the third metal layer; and second and third vias, the metal plate and the third metal layer forming a same layer, the third metal layer being divided into a first pattern area and a second pattern area by the metal plate, the first pattern area and the second pattern area being connected to the second metal layer respectively through the second and third vias, and the mushroom type structure being electrically separated from each of the first and the second pattern areas.