| 摘要 |
A semiconductor device includes an output driver circuit for generating noise on wiring for a power supply using a trigger signal input from measuring equipment and a noise measuring circuit. The noise measuring circuit includes a comparator circuit for comparing a voltage on wiring for the power supply with a reference voltage supplied from the measuring equipment and outputting a result of comparison, and two latch circuits for respectively holding the change of the result of comparison to one state and the change of the result of comparison to the other state, for output to the measuring equipment. The measuring equipment changes the reference potential, monitors times from a change of the trigger signal which becomes a trigger for noise generation, to changes of output signals of the two latch circuits, and plots the reference voltage and timings of the output changes, thereby estimating the waveform of the noise.
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