BAD MEMORY CELL REPLACING METHODS OF SEMICONDUCTOR MEMORY DEVICE

摘要

The memory device comprises a main memory cell array, a spare cell array, a redundant predecoder having a number of outputs, a number of pass-transistors having one end of each channel connected to the output of the redundant pre-decoder and gates conected to a first control node (NDAZ) commonly, and a number of fuses connected to the other ends of the channels and a redundant output end (Vx2). The method comprises connecting a channel of pull-down transistor (NB2) between the redundant output and a ground voltage, turning-on the pass-transistors except one pass- transistor corresponding to a poor cell to turn-off the pull- down transistor and turning-off the pass-transistors, if the substituted column row is poor in the spare cell array, to turn-on the pull-down transistor.