| 摘要 |
PURPOSE:To improve the reliability of a switch circuit by holding an output voltage much lower than the low output level of a front-stage differential switch circuit under the control of a power source side, and turning off the switch circuit regardless of the input of a rear-stage differential switch circuit to which the varied output is inputted. CONSTITUTION:When an IC 20 to be tested is in an input state, a control differential switch circuit 4 in an IC tester output driver 1 is held off. Namely, a high-level base voltage VB5 is applied to a transistor(TR) Q5 and a low-level base voltage VB6 is applied to a TR Q6, which is held off, so that the high level of the front-stage differential switch circuit 2 is determined by the base voltage VB1 to a TR Q1. In this state, pulse voltages are inputted as the voltage VB1 and the base voltage VB2 to a TR Q2 and then the waveform voltage of the VB2 is inputted to the IC 20 as it is, i.e. as a voltage Vi. The voltages VB1 and VB2 are therefore transmitted at a high speed and the operation measurement of the IC in a fast operation state is performed with high accuracy, thereby improving the reliability.
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