| 摘要 |
A semiconductor memory device having an array of memory cells divided into a plurality of blocks including a redundant block, in which each block is treated as a single unit and a faulty block is replaced with the redundant block. Each block has four logic circuits which drives a transistor for pulling up bits lines in a standby state and drives a transistor for pulling up bit lines to prevent data from being lost according to a bit-line pull-up timing signal, a redundant-block enable signal, a block address and a write signal. With this structure, in a faulty block, both of the transistors are always turned off and a supply of currents to the bit lines are cut off. Therefore, even when a block becomes faulty due to a short circuit between the bit lines and the ground potential section, the semiconductor memory device is saved from becoming defective.
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