Patent ID: 7057947

Claim:
A nonvolatile semiconductor memory comprising: a fuse data storage for storing fuse data including replacement data for replacing a first area with a second area in a memory cell array; a fuse data read unit for reading out the fuse data from said fuse data storage; a read control circuit which, when activated, outputs a control signal for reading out the fuse data to said fuse data read unit; an activation control circuit for controlling said read control circuit in accordance with external input wherein said activation control circuit further comprises: a pad connected to said activation control circuit, in which the external input is performed by application of a voltage to said pad; a power-on reset circuit for outputting a power-on reset signal when a voltage reaches a predetermined level after the power source is turned on; and an activation determining circuit which, if the voltage input to said pad is at a first level, activates said read control circuit to output the control signal when the power-on reset signal is output, and, if the voltage input to said pad is at a second level, deactivates said read control circuit so as not to output the control signal even when the power-on reset signal is output.