US Patent 7933159 Semiconductor memory device and system with redundant element

A semiconductor memory device includes a memory cell array, a redundant element, an address specifying circuit configured to select one of a plurality of addresses as a redundancy address in response to a switchover signal, a decoder circuit configured to select the redundant element in response to an externally applied address that matches the redundancy address selected by the address specifying circuit, and a test mode setting circuit configured to change the switchover signal in response to an externally applied input, thereby to cause the redundancy address assigned to the redundant element to be switched between different ones of the plurality of addresses.