Patent ID: 8097815

Claim:
A printed circuit board mounting IC package having plural connection terminals arrayed in lattice, comprising: plural soldering lands arranged in lattice on a principal surface of the printed circuit board, each of which is provided for connecting corresponding one of the plural connection terminals of the IC package and includes a circular portion, circular portions of the plurality of soldering lands having the same area; through-holes penetrating through the printed circuit board from the principal surface to a wiring surface opposite to the principal surface; and through-hole upper lands having a circular shape with larger in diameter than said circular portion of said soldering lands, each one of said through-hole upper lands being concentrically provided around the circumference of corresponding one of the through-holes, said through-hole upper lands being disposed on the principal surface of said printed circuit board, wherein: at least one of the through-holes is surrounded by plural soldering lands in a plan view on the principal surface, and is arranged eccentric from a center of the plural soldering lands surrounding said at least one of the through-holes toward one of the soldering lands surrounding said at least one of the through-holes in a plan view, said one of the soldering lands having a same potential as said at least one of the through-holes and connected to a through-hole upper land of said at least one of the through-holes, a diameter of the through-hole upper land of said at least one of the though-holes overlaps with a diameter of the circular portion of said one of the soldering lands having a same potential, but does not overlap with diameters of the circular portions of said plural soldering lands which are different from said one of the soldering lands having a same potential, in a plan view, so that the circular through-hole upper land of said at least one of the though-holes is physically in contact with the circular portion of said one of the soldering lands having a same potential on the principal surface.