HALBLEITERSPEICHERVORRICHTUNG MIT EINEM REDUNDANTEN BLOCK

摘要

A semiconductor a semiconductor memory device including a plurality of normal blocks containing only normal memory cells without a redundant memory cell and a redundant block containing only redundant memory cells. The device comprises a plurality of normal blocks each having a plurality of normal row and column lines each connected with a plurality of normal memory cells; a redundant block having a plurality of redundant row and column lines each connected with a plurality of redundant memory cells; block decoder for selecting one of the normal blocks in response to first address signals; a redundant column decoder being programmed to select redundant columns replacing normal columns which are containing defective normal memory cells according to the output signals of the block decoder and second address signals, the decoder producing redundant operation signals when a defective normal memory cell is addressed; a redundant clock generator for producing a redundant control clock in response to the redundant operation signals; and a plurality of normal column decoders associated with the normal columns in the respective normal blocks, whereby the decoders all are disabled by the redundant control clock when a defective normal memory cell is addressed, and one of the decoders is enabled by the output signals of the block decoder for selecting a normal column line addressed by the second address signals when a defect-free normal memory cell is addressed.