摘要:
Methods for programming and reading a multi-level-cell NAND flash memory device having plural memory cells are disclosed to reduce the programming time and the reading time. The program method comprises the steps of: (a) programming the zero state memory cells, the first state memory cells, the second state memory cells and the third state memory cells to a zero state, (b) programming the second state memory cells from the zero state to a second state by switching the MSBs of the second state memory cells, and (c) programming the first state memory cells from the zero state to a first state by switching the LSBs of the first state memory cells and simultaneously programming the third state memory cells from the second state to a third state by switching the LSBs of the third state memory cells. The read method comprises the steps of: (d) reading the MSBs of the zero state memory cells, the first state memory cells, the second state memory cells, and the third state memory cells by a first verify signal and a second verify signal, and (e) reading the LSBs of the zero state memory cells, the first state memory cells, the second state memory cells, and the third state memory cells by the first verify signal and a third verify signal. A page buffer is also disclosed to perform the methods for programming and reading a multi-level-cell NAND flash memory device.
摘要:
Methods for programming and reading a multi-level-cell NAND flash memory device having plural memory cells are disclosed to reduce the programming time and the reading time. The program method comprises the steps of: (a) programming the zero state memory cells, the first state memory cells, the second state memory cells and the third state memory cells to a zero state, (b) programming the second state memory cells from the zero state to a second state by switching the MSBs of the second state memory cells, and (c) programming the first state memory cells from the zero state to a first state by switching the LSBs of the first state memory cells and simultaneously programming the third state memory cells from the second state to a third state by switching the LSBs of the third state memory cells. The read method comprises the steps of: (d) reading the MSBs of the zero state memory cells, the first state memory cells, the second state memory cells, and the third state memory cells by a first verify signal and a second verify signal, and (e) reading the LSBs of the zero state memory cells, the first state memory cells, the second state memory cells, and the third state memory cells by the first verify signal and a third verify signal. A page buffer is also disclosed to perform the methods for programming and reading a multi-level-cell NAND flash memory device.
摘要:
A non-volatile memory device with a page buffer having dual registers includes a memory cell array, a selector circuit and a page buffer circuit, the selector circuit being coupled to an exterior data line, the page buffer circuit including a first register and a second register being coupled between the memory cell array and the selector circuit, and the first register and second register being commonly coupled through a sense node. The first and second registers alternately write data to the memory cell array for programming. As one of the first and second registers performs programming, the other register stores data from the data line concurrently. In other words, the second register stores data from the data line when the first register is in programming, whereas the first register stores data from the data line when the second register is in programming.