| 摘要 |
PROBLEM TO BE SOLVED: To shorten measuring time at the time of testing a device by setting the voltage step width applied to the device to a specific multiple of the measuring resolution and performing the measurement by gradually narrowing the step width and, when the device is discriminated as defective, terminating the measurement. SOLUTION: The voltage step width of a ramp wave voltage is set at MINLSB which is the M multiple of the step width V of the measuring resolution required for discriminating the normal/abnormal condition of a device to be measured and data are fetched while a ramp voltage which becomes N/M pieces is applied across the device. Although the then measuring resolution is sufficient when the step width is set to the MINLSB, the measuring time becomes the 1/M of the conventional time, because the device is discriminated as defective when the device has a nonlinear error or differential linear error which is larger than the sum of a discriminated value and M/NLSB. When the device is discriminated as normal, a ramp wave voltage to which the offset voltage corresponding to M/(Nx)LSB is added is applied across the device and, when the nonlinear error, etc., is larger than the sum of a discriminated value and M/(N×2)LSB, the device is discriminated as defective and the measurement is terminated. Similarly, the measurement is repeated by adding an appropriate offset voltage to the ramp wave voltage. Therefore, the measuring time for a defective product can be shortened, while that for a normal product is not changed.
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