[SI-LIST] Re: Power problem
- From: "Dr. Edward P. Sayre" <esayre@xxxxxxxx>
- To: zhang_kun@xxxxxxxxxx
- Date: Mon, 27 Jun 2005 23:12:45 -0400
Zhangkun:
It is unlikely you have an induced field problem; it is more likely you
have not turned on the local DC-DC regulators in the right sequence and you
are getting feed-thru effects. I would check your -48 VDC to intermediate
power and your local DC-DC regulator designs.
Also, the DDR specifications are very clear regarding the turn-on sequence
for DDR products. They must be followed exactly or you run the risk of
latch-up when you access the memory or outright damage.
Hope this helps -
ed sayre
========================
At 10:33 AM 6/28/2005 +0800, you wrote:
>Dear all
>In our product, there is one problem. When the system is turned on, some
>SDRAM would be damaged. The -48V net shape is placed under the 2.5V net
>shape, which is the power supply of SDRAM. I have use VNA to measure the
>coupling between these two power. The coupling is very small. Please give
>me some advice.
>
>Maybe my analysis method is not right.
>
>Best Regards
>
>Zhangkun
>2005.6.28
>
>
>------------------------------------------------------------------
>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 FAQ wiki page is located at:
> http://si-list.org/wiki/wiki.pl?Si-List_FAQ
>
>List technical documents are available at:
> http://www.si-list.org
>
>List archives are viewable at:
> //www.freelists.org/archives/si-list
>or at our remote archives:
> http://groups.yahoo.com/group/si-list/messages
>Old (prior to June 6, 2001) list archives are viewable at:
> http://www.qsl.net/wb6tpu
>
>
>
>!DSPAM:42c0b7c4318036542811310!
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~+
| NORTH EAST SYSTEMS ASSOCIATES, INC. |
| ------------------------------------- |
| "High Performance Engineering & Design" |
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~+
| Dr. Ed Sayre e-mail: esayre@xxxxxxxx|
| NESA, Inc. http://www.nesa.com/ |
| 235 Littleton Road, Ste 2 Tel +1.978.392-8787 |
| Westford, MA 01886 Fax +1.978.392-8686 |
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~+
------------------------------------------------------------------
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 FAQ wiki page is located at:
http://si-list.org/wiki/wiki.pl?Si-List_FAQ
List technical documents are available at:
http://www.si-list.org
List archives are viewable at:
//www.freelists.org/archives/si-list
or at our remote archives:
http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
