| 摘要 |
PURPOSE:To raise an access speed at the time of a memory is operated and to make unnecessary trimming process required for fuse melting, etc., by chang ing over a preliminary memory with a part of the main memory by a latch circuit. CONSTITUTION:The address of a detected false memory is supplied from an address terminal 30 and stored into a ROM 31. By the supply of an electric power source voltage Vdd, the contents of the ROM 13 are read to an address signal line 32 and a latch control signal line 33. Thus, latches 34, 35 36 in an address decoder 37 and a preliminary decoder 38 are started, the decoder is changed over and the program of the decoder 38 is executed. During the energizing, the changing-over condition is continued, the faulty memory address is inputted at the time of usual operation then, the decoder 38 is started and a preliminarily memory 39 is selected. Consequently, it is not necessary to compare addresses, the access speed is raised and the fuse melting, etc., are not necessary.
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