Patent ID: 7471092

Claim:
A test apparatus to test a device under test (DUT) including a low voltage operating section and a high voltage operating section that operates with a predetermined high voltage which is higher than that with which the low voltage operating section operates, the test apparatus comprising: a low voltage applying section that applies a first reference voltage to the low voltage operating section of the DUT; a high voltage applying section that applies, to the high voltage section of the DUT, a second reference voltage which has a higher voltage level than the first reference voltage by a predetermined difference, said second reference voltage defining a voltage level that is to be possessed by an output signal output from the DUT when the output signal indicates a predetermined logical value; a voltage level detecting section that detects a voltage level of the second reference voltage; a signal comparing section that compares the output signal with an expected value signal; a reference voltage comparing section that judges whether the voltage level of the second reference voltage detected by the voltage level detecting section falls within a predetermined expected voltage range; and a judging section that judges whether the DUT is good or bad based on a result of the comparison done by the signal comparing section, under a condition that the voltage level of the second reference voltage falls within the expected voltage.