Patent ID: 7579693

Claim:
A mounting structure of a ball grid array which is mounted on a wiring board in a rectangular shape adapted to be fixed with screws to a mounting member, such as a case body, at four points, wherein the wiring board is provided with screw insertion holes for fixing the wiring board with the screws at the four points, solder banks as ground electrodes are formed around the screw insertion holes and are adapted to be pressure contacted with a ground connecting face which is provided on the mounting member by fixing with the screws, the screw insertion holes at the four points are located in respective corners of an imaginary rectangular outline which is imagined on a board surface of the wiring board, and two of the screw insertion holes diagonally positioned on the imaginary rectangular outline are respectively located in one of corners of the wiring board and at an inward position of the wiring board, while the remaining two screw insertion holes are located at respective intermediate parts of two sides which embrace the corner of the wiring board, the wiring board is divided into a first zone in a rectangular shape which is surrounded by all the four points to be fixed with screws to the mounting member and a second zone in an L-shape outside the first zone, and the ball grid array is mounted on an intersecting area between a vertical area and a transverse area which define the L-shape of the second zone.