Dynamic random access memory

1. Field of the Invention In order to reduce power consumption in a dynamic random access memory (DRAM), block selection information RBDATA indicating whether or not individual blocks in a memory cell array require a refresh is stored at means for latching -and -A circuit for operation prohibition compares a portion RAof a refresh address output by a refresh counter with refresh block specification signals RB () and RB () output by the circuit for latching -and -makes a decision as to whether or not the block indicated by the refresh address needs to be refreshed and prohibits an operation of an RAS system circuit if it is decided that the block does not need to be refreshed. Thus, a self refresh is not performed for a block that does not need to be refreshed to achieve a reduction in power consumption.