| 摘要 |
PROBLEM TO BE SOLVED: To previously detect a failure of an operational amplifier circuit. SOLUTION: Besides an operational amplifier circuit 10 for a product which has a first and a second differential pair transistors 11a, 11b, an operational amplifier circuit 20 for monitoring which has a third and a fourth differential pair transistors 21a, 21b whose gate areas are smaller than those of the transistors 11a, 11b are arranged in the same chip. In the transistors 21a, 21b, variation of offset voltage which is caused by deterioration with time is greater than that of the transistors 11a, 11b, so that failure of the operational amplifier circuit 10 for a product can be detected previously by judging offset voltage of an output terminal OUT2 of the operational amplifier circuit 20 for monitoring. COPYRIGHT: (C)2004,JPO&NCIPI
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