Patent ID: 7332907

Claim:
A semiconductor device having a semiconductor integrated circuit, the semiconductor device comprising: a first plurality of leads, each of the leads for supplying the semiconductor device with a first power source from an outside; a second lead for supplying the semiconductor device with a second power source having a voltage different from a voltage of the first power source from an outside; a first internal power source line directly connected to an internal circuit including a plurality of logic circuits of the semiconductor integrated circuit, the first internal power source line for supplying the internal circuit of the semiconductor integrated circuit with the first power source; a second internal power source line directly connected to the internal circuit of the semiconductor integrated circuit, the second internal power source line for supplying the internal circuit with the second power source; a first plurality of internal terminals, each of the internal terminals coupled to a corresponding one of the first plurality of leads and supplying the first internal power source line with the first power source from a corresponding one of the first plurality of leads; a second internal terminal coupled to the second lead and supplying the second internal power source line with the second power source from the second lead; a switching circuit portion including a plurality of switching circuits, each of the plurality of switching circuits interposed between a corresponding one of the first plurality of internal terminals and the first internal power source line; and a voltage change detecting portion connected to the first and the second internal power source lines, the voltage change detecting portion sampling a first voltage of the first power source input through one of the plurality of switching circuits and comparing the first voltage sampled therein with a second voltage of the first power source input through another one of the plurality of switching circuits.