| 摘要 |
PURPOSE:To perform high-accuracy inspection by calculating a correcting value from data of an external clock set in a register and data of a timing error due to a fetching circuit system for the clock data, and controlling a delay time according to the correcting value. CONSTITUTION:Data on the period of the external clock 16 is set in the register 20 and data on the timing error due to the fetch circuit system for the external clock 16 is set in the other register 22. A subtracting circuit 24 calculates the difference between the set data in the registers 20 and 22 and supplies the result to the variable delay circuit 18 as data on the timing correcting value. The delay time of the circuit 18 is controlled according to the timing correcting value. Consequently, the data on the period of the operation clock of an IC to be inspected is set during an external test and a multiplexer 12 is controlled to an external side. Consequently, the external clock 16 after timing correction is inputted as a rate clock to a phase generator 14 to synchronize the operation of the IC to be inspected with the internal operation of an IC inspecting device, thereby preforming high-accuracy inspection.
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