[SI-LIST] Re: DDR3 DQ-DSQ skew over temperature
- From: Hermann Ruckerbauer <Hermann.Ruckerbauer@xxxxxxxxxxxxx>
- To: si-list@xxxxxxxxxxxxx
- Date: Wed, 07 Jan 2015 19:26:49 +0100
Hello,
the output timings are aligend by the DLL circuit on the DRAM. this
should compensate Voltage/process/Temperature changes and align DQ/DQS
to the incoming clock.
In addittion both output circuits DQS and DQ should heat up by the same
amount, so the timing of both would change and especially DQS vs. DQ
timings should stay anyhow the same..
Hermann
EKH - EyeKnowHow
Hermann Ruckerbauer
www.EyeKnowHow.de
Hermann.Ruckerbauer@xxxxxxxxxxxxx
Itzlinger Strasse 21a
94469 Deggendorf
Tel.: +49 (0)991 / 29 69 29 05
Mobile: +49 (0)176 / 787 787 77
Fax: +49 (0)3212 / 121 9008
Am 07.01.2015 um 14:05 schrieb Boris Bakshan:
> Dear all,
> In read leveling procedure DQS and DQ signals are aligned in the controller
> so that optimum phase shift between the signals is achieved.
> What happens on temperature and voltage drift?
> If the read leveling calibration was originally performed at 0 degrees and
> -5% of VDD/VDDQ and certain optimal values had been concluded then if
> temperature now rises to 85C and voltage +5% *then it might not be optimal*
> since tDQSQ and tDH might have changed (and probably timing parameters of
> the controller had also changed).
> How is this being settled?
> Is it common to re-perform read leveling with temperature and voltage
> changes?
>
> Thank you.
>
>
> ------------------------------------------------------------------
> To unsubscribe from si-list:
> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>
> or to administer your membership from a web page, go to:
> //www.freelists.org/webpage/si-list
>
> For help:
> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>
>
> List forum is accessible at:
> http://tech.groups.yahoo.com/group/si-list
>
> List archives are viewable at:
> //www.freelists.org/archives/si-list
>
> Old (prior to June 6, 2001) list archives are viewable at:
> http://www.qsl.net/wb6tpu
>
>
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List forum is accessible at:
http://tech.groups.yahoo.com/group/si-list
List archives are viewable at:
//www.freelists.org/archives/si-list
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
