| 摘要 |
PURPOSE:To reduce reading errors by grounding the power supply terminal of a semiconductor integral circuit device having an SEPP (Single Ended Push- Pull) circuit in an output stage and supplying a ground terminal with a negative voltage. CONSTITUTION:Grounding the power supply terminal 5 of a semiconductor integrated circuit device 2 to be measured having an SEPP circuit 1 in an output stage and applying a negative voltage, for example, -20V to a ground terminal 6 are equivalent to applying the power supply voltage VCC of 20V between the terminals 5 and 6. Applying a negative voltage, for example, -18V to a plus input terminal 7 in the above-described condition is equivalent to applying the input voltage of 2V to the terminal 7 relative to the terminal 6. By the operations of turning on or off transistors Tr1 and Tr2 in response to above-described input signals, a desired waveform output with an intermediate voltage between the power supply voltage VCC and a voltage GND, namely, -10V as a reference can be obtained. When the measuring accuracy of a voltmeter 3 is set to a 0.1V unit, the measured value of -0.5V is indicated by the voltmeter 3 to enable the measured value to be read in a condition wherein the measuring range of the voltmeter 3 is set small.
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