SEMICONDUCTOR MEMORY DEVICE

• Main Author: BABA FUMIO
• Format: Patent
• Language: English
• Published: 30.01.1991
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; INFORMATION STORAGE; PHYSICS; SEMICONDUCTOR DEVICES; STATIC STORES

PURPOSE:To obtain the semiconductor memory device of large capacity to be completely operated at a low cost by storing the presence and absence of a defective memory cell for each block in the memory cell of each memory element and switching a bus line so as to select the other memory element when the block equipped with the defective memory cell is designated. CONSTITUTION:A control means 6 stores the presence and absence of the defective cell in the form of a map for each block in each memory element 1 to a ROM, etc. When an address signal ADD designate one row, which is composed of M-pieces of the elements 1 more than a unit bit number N of data, through a designating means 3, the means 6 refers the contents of the ROM. In the case of a block X equipped with the defective bit, a bus switching means 5 is controlled and a bus 2 is switched. Then, out of external buses 4, one corresponding bus is connected. Thus, the data of the N bits can be read from the element 1 and the device of the large capacity to be stably operated can be obtained at a low cost.