Non-volatile semiconductor memory device reading and writing multi-value data from and into pair-cells
US6847555B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 16, 2003 |
| Grant date | Jan 25, 2005 |
| Priority date | — |
| Expiry date | Jul 11, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C2211/5621
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A non-volatile semiconductor memory device includes: a memory cell array in which a plurality of electrically rewritable and non-volatile memory cells are arranged; a sense amplifier circuit configured to write M-value data (where, M is an integer equal to 4 or more) to pair-cells each constituted by simultaneously selected first and second memory cells connected to a pair of bit lines in the memory cell array, the M-value data being defined as a combination of different threshold levels of the first and second memory cells in M threshold levels to be set at each memory cell, and read M-value data stored in each pair-cell by sensing a difference between cell currents of the first and second memory cells; and a controller configured to control data write and read operations for the memory cell array.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.