[SI-LIST] Re: help me
- From: Stefan Ludwig <ludwig@xxxxxxxxxxxxxxxxx>
- To: zhang_kun@xxxxxxxxxx, jagaveer25@xxxxxxxxxxx
- Date: Fri, 03 Feb 2006 09:46:52 +0100
Jagaveer, Zhangkun,
Zhangkun is right, 3 Ohms on a board with mounted chips is not an issue.
The reason is because of leakage current in transistors. As process
technology progresses (180nm -> 130nm -> 90nm ...), the leakage current
in a transistor gets bigger. That is, a transistor, even when it is
"off", will have some current flowing through it. Also, you can pack
more transistors onto a chip. Therefore, you end up with tens to
hundreds of millions of leaky transistors, which leads to a low
resistance when measured with an Ohm-meter.
Cheers,
Stefan Ludwig
zhangkun 29902 wrote:
>Dear jagaveer
>
>Do not worry about the problem. I have met this kind of problem for several
>times. When the IC is soldered on the PCB, the dc resistance between power and
>ground is very small.
>
>However, I am not sure the reason. The IC vendor did not explain it:(
>
>Best Regards
>
>Zhangkun
>2006.2.3
>
>
>******************************************************************************************
> This email and its attachments contain confidential information from HUAWEI,
> which is intended only for the person or entity whose address is listed
> above. Any use of the information contained herein in any way (including, but
> not limited to, total or partial disclosure, reproduction, or dissemination)
> by persons other than the intended recipient(s) is prohibited. If you receive
> this e-mail in error, please notify the sender by phone or email immediately
> and delete it!
> *****************************************************************************************
>
>----- Original Message -----
>From: jagaveer25 <jagaveer25@xxxxxxxxxxx>
>Date: Friday, February 3, 2006 12:25 pm
>Subject: [SI-LIST] help me
>
>
>
>>Hi folks,
>>
>>
>>I have done in one PCB. It is 12 layer board
>>
>>I have used 4 digital signal processor and one field programmable
>>gate array for this pcb .
>>
>>Dsp side I have used 3 pwr supplies
>>
>>1v
>>1.5v
>>2.5v
>>before I have populated that dsp I have checked between the all
>>pwr
>>supply and gnd resistance is very high resistance but
>>after I have populated that 3 dsp I have checked between the
>>1Vpwr
>>supply and gnd resistance is only 3 ohms
>>
>>my 1v pwr section is 20A design
>>
>>I can't understand this type of problem
>>Can u give any solution for this problem I have appreciate it
>>
>>Thanks
>>V.jagaveer
>>
>>
>>
>
>
>
--
Ludwig Systems Engineering Consulting - Design - Implementation
WWW: www.ludwigsystems.com System Architectures - FPGAs - PCBs
Ph/Fx: +41-43-355-58-73/74 Hardware - Firmware - Software
------------------------------------------------------------------
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:
