| 摘要 |
PURPOSE:To prevent flowing of a stand-by electric current, to make an occupied area smaller and to suppress the delay of the access time by connecting and programming the source of the MOS transistor of the memory cell to the elec tric power source of the different electric potential and making a load transistor unnecessary. CONSTITUTION:The source of a memory cell of a memory cell array 15 is connected to a high electric potential electric power source VDD and a low electric potential electric power source VSS in accordance with the program, and formed by a transistor Trij of the matrix arrangement. Through a full decoder 11, in all lines P1, P2..., only one line is a level of the electric power source VDD, and others are wholy a level of the electric power source VSS. For example, when a line P1 is a level of the electric power source VDD and Tr11, Tr21, etc. are on, the memory contents of a level of the electric power source VSS and a level of the electric power source VDD are read at bus lines B1 and B2 respectively, and outputted through level compensating circuits 171 and 172. With the constitution where the load transistor is not necessary, the mask ROM, in which the stand-by electric current will not flow, the occupied area is small and the access time is not late, is obtained. |
