Abstract: An adapter has a body having a plate-like shape, a holding portion which holds the semiconductor package on a first surface of the body to be electrically connected to terminals of the semiconductor package, and first terminals provided on a second surface of the body and electrically connected to the fitting portions. The adapter is designed mountable to a board via a socket by inserting the first terminals into the socket.

Abstract: A semiconductor device is provided in which function modes thereof can be changed without difficulty and failure analysis can be conducted in an apparatus in which the semiconductor device is mounted. A semiconductor device uses a ball grid array package and includes: a semiconductor chip that is provided within the semiconductor device and has a pad; a detection via hole connected to the pad; a solder ball that is attachable to and detachable from the detection via hole and connects or disconnects a power supply electrode of a substrate on which the semiconductor device is mounted and the detection via hole in correspondence to attachment or detachment of the solder ball to or from detection via hole, respectively; and a mode switching unit that detects a voltage level of the pad connected to the detection via hole and switches function modes in the semiconductor device depending on the voltage level.