A block repair device is disclosed for use in a semiconductor memory having an
array including a defective cell and a redundant row. The block repair device includes
a set of fuses, antifuses, or flash EEPROM cells to store a block repair configuration
that determines the dimensions (e.g., the number of rows and columns spanned) of
a repair block used to repair the defective cell. Routing circuitry, such as multiplexer
circuitry, in the block repair device is directed by the stored block repair configuration
to output selected row and column address bits from received row and column addresses
in a selected ratio. Comparison circuitry in the block repair device then compares
the row and column address bits output by the routing circuitry with a stored portion
of the address of the defective cell that defines the repair block. When a match
occurs, the comparison circuitry implements a block repair by activating the redundant
row and by causing data to be written to or read from the activated redundant row.
