Degradation defection methods for electronic circuits

A degradation diagnosis method that detects the degradation symptoms of electronic cards earlier and with higher sensitivity than previous techniques is presented. One type of degraded IC is obtained experimentally by applying a low surge voltage. For the case of the op-amps, there exists a quantitative relation between the degradation of the IC predicted from the increasing off-set current and the correlation with output noise. The root-mean-square value of the noise is an effective index of degradation detection. A method based on a measurement of the minimum value of supply voltage necessary to maintain the correct logical operation is effective in detecting degraded TTLs. An automatic instrument for degradation detection of electronic cards is developed, and its effectiveness is verified.