OUTPUT CIRCUIT FOR A DOUBLE DATA RATE DYNAMIC RANDOM ACCESS MEMORY, DOUBLE DATA RATE DYNAMIC RANDOM ACCESS MEMORY, METHOD OF CLOCKING DATA OUT FROM A DOUBLE DATA RATE DYNAMIC RANDOM ACCESS MEMORY AND METHOD OF PROVIDING A DATA STROBE SIGNAL
US6381194B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Apr 20, 2001 |
| Grant date | Apr 30, 2002 |
| Priority date | — |
| Expiry date | Apr 20, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C2207/107
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for synchronizing output data and data strobe signals uses internal interleaved clock signals in a double data rate (DDR) DRAM that are synchronized with an external clock. A delay-locked loop internal to the DDR DRAM is locked to an external clock signal and generates the internal interleaved clock signals. The internal interleaved clock signals are delay matched with the external clock signal as they propagate through timing circuitry coupled to latency and burst length selection signals. A data strobe signal is generated using clock signals from the delay-locked loop and is synchronized with the internal interleaved clock signals. The data strobe signal and the data are coupled via paths having comparable numbers and types of delay elements to provide output data and data strobe signals having predetermined delay relationships with the external clock signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.