Patent ID: 7082066

Claim:
A semiconductor memory having a plurality of regular sectors and a spare sector that can be replaced from a regular sector, comprising: a regular sector selection signal generating circuit and a spare sector selection signal generating circuit that generate a regular sector selection signal for selecting said regular sector and a spare sector selection signal for selecting said spare sector respectively in response to an address change signal; a redundancy memory that stores replacement information replacing the regular sector with said spare sector, wherein said replacement information is read out in response to said address change signal; and a reference redundancy memory having the same memory elements as said redundancy memory, in which stored information of said memory elements is read out in response to said address change signal, and which generates an output signal that changes when said readout is completed, wherein either said regular sector selection signal or said spare sector selection signal is set to a deselected state based on the replacement information read out from said redundancy memory in response to a change in the output signal of said reference redundancy memory.