Output driver capable of controlling slew rate of output signal according to operating frequency information or CAS latency information
US7035148B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 30, 2003 |
| Grant date | Apr 25, 2006 |
| Priority date | — |
| Expiry date | Aug 12, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C7/222
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An output driver effectively controls the slew rate of an output signal according to CAS latency information including frequency information of an operating clock signal or according to frequency information obtained by detecting the frequency of the operating clock signal. The output driver includes an output terminal, a pull-up driver which pulls-up the output terminal, and a pull-down driver which pulls-down the output terminal. Also, the output driver further includes a mode register set (MRS) which stores CAS latency information of the semiconductor memory device. Driving capabilities of the pull-up driver and the pull-down driver are varied in response to the CAS latency information. The output driver may include a frequency detector which detects and stores the operating frequency of the semiconductor memory device. In this case, the driving capabilities of the pull-up driver and the pull-down driver are varied in response to output signals output from the frequency detector.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.