| 摘要 |
PURPOSE:To estimate the life of an integrated circuit such as ring oscillator economically and accurately by incorporating a simple added circuit containing a detection circuit, a voltage addition circuit and a recorder. CONSTITUTION:In detection circuits D to which outputs from (n) pieces of DUTs such as ring oscillator are inputted respectively, outputs of the DUTs applied to an input terminal 1 are provided to a half-wave rectification diode 6 only corresponding to an AC portion of the DUT outputs via HPF comprising a bias resistance 5 and a series capacitor 4. When the AC output of the DUTs is small, it is amplified with a preamplifier 2 containing a capacitor 2a and an amplifier 2b. The detection DC output 9 obtained across a smoothing capacitor 7 and a clamper diode 8 connected in parallel thereto after a half-wave rectification with the half-wave rectification diode 6 are clamped to a fixed diode built-in voltage with the clamper diode 8 and inputted into a voltage adder. Outputs of the respective DUTs applied to a voltage adder 11 are each a fixed value V0 and hence, the adder outputs is nV0.
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