[SI-LIST] Re: DDR3 Vref and Vtt plane
- From: Chockalingam Selvaraj <chockalingam.s@xxxxxxx>
- To: Alfred Lee <alfred1520list@xxxxxxxxx>, "deepaksiengg@xxxxxxxxx" <deepaksiengg@xxxxxxxxx>, "si-list@xxxxxxxxxxxxx" <si-list@xxxxxxxxxxxxx>
- Date: Mon, 6 Dec 2010 15:00:09 +0530
Hi Deepak,
I agree with Lee: Vref is supposed to track the variations in the 1.5V plane
feeding the DDR3 circuits.
Hence, having a R-divider close to the Vref pin will help.
If you are having 3 separate supplies for the 3 circuits, then Vref has to be
from the corresponding 1.5V
Usually Vref in VTT regulators have the R divider inbuilt, we can share this
Vref among the ICs provided the current drive on this pin is large enough for
all the devices. You cannot short Vref and Vtt.
By the way, what do you mean by robust results? Any particular issue in your
current board?
Thanks and regards
Chockalingam.S (Ck)
Thanks and regards
Chockalingam.S (Ck)
________________________________________
From: si-list-bounce@xxxxxxxxxxxxx [si-list-bounce@xxxxxxxxxxxxx] On Behalf Of
Alfred Lee [alfred1520list@xxxxxxxxx]
Sent: Sunday, December 05, 2010 1:48 AM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: DDR3 Vref and Vtt plane
> I think it is not necessary to use a regulator, In DDR3,Vref is very
Sorry about not checking the spec out. (Writing on cell phone having no access
to references)
Aren't Vref suppose to track VDDQ? How would a regulator track VDDQ? Is one not
supposed to use a regulator for Vref? Thanks.
--
Sent from my Android phone with K-9 Mail. Please excuse my brevity.
------------------------------------------------------------------
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 technical documents are available at:
http://www.si-list.net
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
::DISCLAIMER::
-----------------------------------------------------------------------------------------------------------------------
The contents of this e-mail and any attachment(s) are confidential and intended
for the named recipient(s) only.
It shall not attach any liability on the originator or HCL or its affiliates.
Any views or opinions presented in
this email are solely those of the author and may not necessarily reflect the
opinions of HCL or its affiliates.
Any form of reproduction, dissemination, copying, disclosure, modification,
distribution and / or publication of
this message without the prior written consent of the author of this e-mail is
strictly prohibited. If you have
received this email in error please delete it and notify the sender
immediately. Before opening any mail and
attachments please check them for viruses and defect.
-----------------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------
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 technical documents are available at:
http://www.si-list.net
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:
