Abstract: A semiconductor memory device has a plurality of memory cell arrays, each with a normal cell array and a spare cell array. Fuse circuits are programmable to substitute a spare-cell-array word line for a defective word line in any normal cell array. When a defective word line is addressed, a fuse circuit activates a spare-cell-array word line, and also activates a redundancy signal line. A single redundancy signal line is shared by all fuse circuits and block select circuits. Block select circuits normally enable the cell array that includes the defective word line, however, the block select circuits are disabled when the defective word line has been replaced by a spare word line an another block.

Abstract: An internal supply voltage generation circuit, producing an internal supply voltage during a normal mode of operation and an external supply voltage during a burn-in mode of operation. The circuit including a plurality of fuses, the operation of which establishes the burn-in mode of operation, and controls a variable burn-in voltage level.

Abstract: A charge pump circuit of a substrate voltage generator used for a semiconductor memory device, comprising a first transistor whose channel is connected between a first pumping capacitor and a substrate node and a second transistor whose channel is connected between a second pumping capacitor and the substrate node, whereby a negative voltage generated by the first pumping capacitor in response to the substrate voltage and clock signals turns on the second transistor which performs charge pumping from the substrate node. Thus the substrate voltage is made to have sufficient coupling-down so as to stabilize the substrate voltage even with a low source voltage.