| 摘要 |
PROBLEM TO BE SOLVED: To accurately measure deterioration of an element (particularly a transistor) of a semiconductor integrated circuit. SOLUTION: The deterioration detection circuit (8) including a frequency measuring instrument (2) for outputting data of the frequency of a ring oscillator (1) and a determination circuit (7) for determining whether the ring oscillator (1) is acceptable or not is formed. The determination circuit (7) receives: frequency data; environment-dependent characteristic data (15), (16), (17) indicative of the relation between the operating environment and oscillation frequency of the ring oscillator (1); tolerance range data (6) permitted as an oscillation frequency of the ring oscillator (1); and environment-specific data (13), (14) during operation of the ring oscillator (1). An ideal oscillation frequency being an ideal oscillation frequency of the ring oscillator (1) is calculated based on the environment-specific data (13), (14) and the environment-dependent characteristic data (15), (16), (17), and whether the frequency data are included in a condition corresponding to the tolerance range data (6) is determined. COPYRIGHT: (C)2011,JPO&INPIT
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