| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a mask ROM and the like capable of realizing an accurate readout. SOLUTION: One of bit lines BL0-BLn is selected by a multiplexer 12 to output a readout current to a current detecting section 14a via a resistor 13. The readout current is 0 or has a variable value larger than the minimum current I in accordance with stored contents at a plurality of MOS 11i ,j which are other than the MOS 11i ,j selected by a word line WLi but located on the same bit line as the selected one. A DMOS 150 and a plurality of EMOS 151 -157 connected in series are provided on a dummy bit line DBL which is provided adjacent to and in parallel with a bit line BLn. Gates of the DMOS 150 and the plurality of EMOS 151 -157 are respectively connected to and fixed at 'L' and 'H', and the dummy bit line DBL is connected to the current detecting section 14a via a resistor 16 having a resistance value of 2R. Thus, the dummy bit line DBL is always supplied with 1/2 of the minimum current I at the bit lines BLO-BLn, resulting in an accurate readout.</p> |
