CIRCUIT TESTER

PROBLEM TO BE SOLVED: To reduce memory capacity by storing a compressed data sequence in a memory, decompressing the data through a sequencer and transferring the decompressed data to a DUT(device under test) and comparing a response data with a decompressed data sequence. SOLUTION: A compressed data sequence and a sequencer instruction from a sequencer 11 are stored in a memory 12. A clock 30 triggers each electronic circuit and the sequencer 11 stores the compressed data sequence and the sequencer instruction from the memory 12 through a bus 20 and decompresses them according to the sequencer instruction. When a pin 18 to be connected with the DUT is an input pin, the compressed data sequence is transferred to a driver 16 through a bus 21, a formatter 13 and a bus 23. In case of an output pin, a response data sequence is fed to a comparator 14 through a receiver 17 and a bus 24 and when it does not match a data sequence generated from the sequencer 11, the content is written in an error memory 15. This arrangement reduces the capacity of the memory 12.