| 摘要 |
PURPOSE:To reduce the number of reserve memories and make small an area of a chip by using an unsatisfactory RAM having plural unsatisfactory memory cells and operating it as one RAM. CONSTITUTION:When a memory cell in which an address signal AN is selected at a high electric potential is inferior, a fuse H2 is cut off. During a reading operation of a RAM, when the high electric potential is impressed to an address signal input terminal 4, an output circuit 3 is inactive by a comparison circuit 2 to be a non-selected condition. When a low potential is impressed to the terminal 4, the circuit 3 is activated. When the memory cell is faulty in which the terminal 4 is selected at the low electric potential is inferior, by cutting off a fuse H1, similarly, only when the faulty memory cell is selected, the circuit 3 can be inactive. In this way, by using two RAMs is which an output is in active when the faulty cell is selected, they can be operated as one RAM.
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