A microelectronic system includes a printed circuit board and a semiconductor package mounted on the printed circuit board. The printed circuit board includes a laminated core having an internal conductive layer and a build-up layer. The build-up layer includes a top conductive layer. Microvias are disposed in the build-up layer to connect the top conductive layer with the internal conductive layer. A power/ground ball pad array is disposed in the top conductive layer. The power/ground ball pad array includes power ball pads and ground ball pads arranged in an array with a fixed ball pad pitch P. The power/ground ball pad array includes a 4-ball pad unit area comprised of only one ground ball pad and three power ball pads, or comprised of only one power ball pad and three ground ball pads. The 4-ball pad unit area has a rectangular shape and a dimension of about 2P×2P.