LSI TESTING DEVICE

PURPOSE:To enable diagnosis of an LSI even in the case the waveform shape is varied for every cycle by detecting rise/fall edges of the test signal which is inputted after being switched from the supply to the LSI to be tested and calculating the quantity of detected edges. CONSTITUTION:The test signal is supplied to edge detecting circuits 101,102 through a relay 306 and a voltage comparator 307, and the rise and fall edges of test signal are respectively detected as clock pulses. the quantity of these clock pulses are counted by a counter 103 for the rise edge and by a counter 104 for the fall edge. The counted results for every one cycle are stored in a memory 105, and finally by means of comparing them with the quantity of edges having desired waveform shape, the normal/defective state of waveform shape is decided. When the waveform shapes are different for every cycle, the generation of rise/fall edges can be all detected in each cycle, therefore, the diagnosis can be made in the case the waveform shapes are varied for every cycle.