| 摘要 |
A tester detects an abnormality in a quiescent power supply current of a device under test. In the tester, a programmable voltage generation source controls a power supply unit, providing a device under test with power. A test pattern generator applies test patterns repeatedly to the device under test. Power supply current to the device under test is converted into voltage values by a detection resistor. A spectrum analyzer unit finds a differential between voltage values occurring between opposite ends of the detection resistor, and voltage values proportional to power supply current values of a device known to perform properly, as measured beforehand. The spectrum analyzer ouputs a power of a fundamental wave of a frequency spectrum obtained by applying the EFT method to the differential. The decision unit prestores spectrum reference values Po as the maximum values for power of the fundamental wave, giving a decision that the quiescent power supply current is abnormal if the power is in excess of the spectrum reference value. The decision is sent out to a CPU, and displayed on a display unit.
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