Abstract: A printed wiring board includes a base material, a plurality of electrode pads to which an electronic component is soldered, the electrode pads being formed on a surface of the base material, a molten-solder introducing protrusion formed on the surface of the base material and connected to each of the electrode pads to draw molten solder into the electrode pad during soldering, and a molten-solder separating protrusion formed on the surface of the base material and connected to each of the electrode pads to help separation of molten solder from the electrode pad at a moment of separation of molten solder, wherein the molten-solder introducing protrusion, the electrode pad, and the molten-solder separating protrusion are aligned in line.

Abstract: A printed wiring board has a solder-land group for placing a quad flat package IC, and the solder-land group consists of front solder-land groups and rear solder-land groups. The printed wiring board includes rear solder-drawing lands that are positioned adjacent to rear solder-land groups, that have front edges each of which is substantially parallel to a longitudinal direction of rear solder lands constituting the rear solder-land group and has a length approximately equal to or longer than that of the solder lands in the longitudinal direction, that are separated into two parts in a horizontal direction with respect to a traveling direction of solder flow such that a gap between the respective two separate lands is made wider in its rearward portion than that in its frontward portion, and that have a slit substantially parallel to the longitudinal direction near the front edge.

Abstract: A printed wiring board has a solder-land group for placing a quad flat package IC, and the solder-land group consists of front solder-land groups and rear solder-land groups. The printed wiring board includes rear solder-drawing lands that are positioned adjacent to rear solder-land groups, that have front edges each of which is substantially parallel to a longitudinal direction of rear solder lands constituting the rear solder-land group and has a length approximately equal to or longer than that of the solder lands in the longitudinal direction, that are separated into two parts in a horizontal direction with respect to a traveling direction of solder flow such that a gap between the respective two separate lands is made wider in its rearward portion than that in its frontward portion, and that have a slit substantially parallel to the longitudinal direction near the front edge.