| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve a sensing margin to an off cell by impressing the same voltage to main bit lines excluding word lines and a source line or a higher voltage than that of the word lines to the main bit lines. SOLUTION: A NOR type mask ROM is constituted of a cell array 100, an address buffer circuit 200, a voltage generation circuit 300, a block and word line selection circuit 400, a column selection circuit 500, a column selection- switching circuit 600 and a sensing and precharging circuit 700. The array 100 has a NOR type memory cell, comprising a plurality of array blocks 110 divided in a column direction. A row address RA is input from the address buffer circuit 200 to the block and word line selection circuit 400, whereby a selection signal BLOCKi for selecting one of the array blocks 110 of the array 100, etc., is output from the selection circuit 400.</p> |
