| 摘要 |
PURPOSE:To provide a ROM having a small occupying area. CONSTITUTION:A ROM memory cell MC has a memory cell transistor 1 and a plurality of reference potential transmission lines 4, 5a, 5b. Storage information of the cell MC is determined according to the connecting state of a source terminal of the transistor to the transmission line. A reference potential is transmitted from a reference potential generator 50 to the lines 4, 5a, 5b. The transmission lines are disposed in parallel with a bit line 3. Accordingly, data stored in the cell MC can be altered by varying the potentials of the lines 4a, 5a, 5b, a plurality of address data can be stored in one memory cell thereby to reduce the number of ROM cells, thereby obtaining a ROM having a small occupying area. The bit line 3 and the lines 4a, 5a, 5b are disposed in parallel to charge/discharge a current to the transmission lines through the cells, and hence variation in the potential of the transmission line can be prevented, thereby rapidly and effectively reading data. |
