[SI-LIST] Re: ODT in DDR3
- From: Hermann Ruckerbauer <hermann.ruckerbauer@xxxxxxxxxxxxx>
- To: prasad <hariprasad.palli@xxxxxxxxx>
- Date: Tue, 24 Nov 2009 19:54:18 +0100
Hi Venkat,
I have just sent one answer to another post regarding DDR2 vs. DDR3.
Here are the different values of DDR3 ODT mentioned, that you can
program in the MRS.
Here the link to the presentation:
http://www.eyeknowhow.de/index.php?option=com_rokdownloads&view=folder&Itemid=17&id=2:presentations
The reason for the different ODT values are the different configurations where
you can use your DRAM and adjust its behavior according to your system.
For a highly loaded system with many reflections you can use a lower value of
ODT, and for a light loaded system (e. g. Point to Point) you can use e. g.
only the 120 Ohm (dynamic) ODT (or no termination at all) in order to save
power.
To really figure out what your configuration will need you have to do some
simulations and maybe calculate a timing budget ...
regards
Hermann
EKH - EyeKnowHow
Hermann Ruckerbauer
www.EyeKnowHow.de
Hermann.Ruckerbauer@xxxxxxxxxxxxx
Veilchenstrasse 1
94554 Moos
Tel.: +49 (0)9938 / 902 083
Mobile: +49 (0)176 / 787 787 77
Fax: +49 (0)3212 / 121 9008
prasad schrieb:
> Hi All,
> what are the different values of ODT for DDR3? how do they choose them and
> when do they program it for different values? and why?
>
> please help me with your inputs....
>
>
> Thanks,
> venkat
>
>
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