Impedance matching circuit, input-output circuit and semiconductor test apparatus

Abstract

A characteristic test of a DUT having a weak transmission line driving capability can be performed with a simple configuration at a low cost. An impedance matching circuit 90 is connected between a transmission line 70 and a DUT 10 in an input-output circuit 80 of a semiconductor test apparatus 1. The impedance matching circuit 90 is constituted of: a resistance (a first resistance Rtp 81-1 and a second resistance Rts 81-2); an analog computing unit having two inputs and one output (a first analog computing unit 82-1 and a second analog computing unit 82-2) which multiplies a voltage from one end of this resistance by a predetermined number, subtracts a voltage at the other end of the resistance from the voltage multiplied by the predetermined number and outputs a voltage obtained by this subtraction; and a buffer (a first buffer 83-1 and a second buffer 83-2) which outputs an output signal from this analog computing unit with a low impedance. The impedance matching circuit 90 outputs an output signal from the DUT 10 with a low impedance, and can drive the transmission line 70.

Dependencies are inferred from the claim text.