Abstract: A semiconductor test apparatus including a current load circuit, by which ringing otherwise caused during a high-speed digital test can be prevented on both the overshoot and undershoot sides, is provided. In a current load circuit, a source current load circuit and a sink current load circuit are associated with a first current load switching voltage setting circuit and a second current load switching voltage setting circuit, respectively, which can be set separately so that high and low levels of the signal waveform are clamped to respective potentials to clip overshoot and undershoot in the ringing waveform. A rectifying diode circuit allows a sink current to flow when overshoot is about to occur, and allows a source current to flow when undershoot is about to occur.

Abstract: A waveform formation device according to the present invention comprises a memory storing rise time data and fall time data related to an output waveform, a first timing generator for producing a set signal at a timing related to the rise time data, and a second timing generator for producing a reset signal at a timing related to the fall time data. A flip flop circuit of the device produces an output signal which rises in response to the set signal and falls in response to the reset signal.