Read only memory having localized reference bit lines
US5602788A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 7, 1996 |
| Grant date | Feb 11, 1997 |
| Priority date | — |
| Expiry date | Jun 7, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C17/12
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A growable read only memory (ROM) provides improved performance over a wide range of array sizes by incorporating a localized reference bitline that accurately tracks changes in loading and variations in process parameters. The reference bitline is input into one side of a differential sense amplifier while a selected data bitline is input into the other side. The reference bitline is precharged and includes two columns, a first column includes devices that are matched to memory cell devices wherein a device of the selected word line will be selected to discharge the referenced bitline. The second column includes a recessed oxide device corresponding to each memory cell in the column. The combination of the two columns ensures that the reference bitline will discharge at a predetermined rate that tracks the rate at which a selected contact programmed memory cell discharges.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.