发明授权
US5452251A Semiconductor memory device for selecting and deselecting blocks of word lines 失效
用于选择和取消选择字线块的半导体存储器件

Semiconductor memory device for selecting and deselecting blocks of word
lines
摘要:
A semiconductor memory device has 2.sup.n word lines, a plurality of bit lines, a plurality of nonvolatile memory cells disposed at each intersection of the word lines and the bit lines, a write circuit for writing data to a memory cell located at an intersection of selected ones of the word lines and the bit lines, and a sense amplifier for reading data out of the memory cells. Further, the semiconductor memory device comprises a first unit for simultaneously selecting a block of 2.sup.m (n>m) word lines among the 2.sup.n word lines, and a second unit for not selecting a block of 2.sup.k (m>k) word lines among the 2.sup.m word lines. The second unit does not select the block of 2.sup.k word lines, and selects a block of 2.sup.k word lines prepared outside the 2.sup.n word lines when any one of the 2.sup.k word lines among the 2.sup.m word lines is defective. Consequently, redundant word lines are effectively employed, write and verify operations are stable, and thereby the yield and performance of the semiconductor memory device are improved.
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