[SI-LIST] Re: Ground vias around signal via
- From: steve weir <weirsi@xxxxxxxxxx>
- To: si-list@xxxxxxxxxxxxx
- Date: Wed, 15 Oct 2014 14:04:25 -0700
All vias that stitch the top and bottom of a Vss - Vss cavity together,
and bypass capacitors that stitch a Vdd - Vss cavity together are part
and parcel of the return path for all signals that penetrate the cavity.
Given some arbitrary stack-up with arbitrary ICs and bypass design and
arbitrary number of signals penetrating a cavity, there is insufficient
information to say whether or not a given noise and cross talk budget
will be satisfied. If good practices are followed then often the vias
that exist naturally as part of the power interconnect are adequate. If
they are not, then something has to change: Signal routing, IE what
penetrates a given cavity, stack-up, and/or stitching.
This presentation shows examples with real measured data.
http://www.ipblox.com/pubs/SVCEMC_Feb_2012/How%20Bad%20is%20Bad.pdf
Best Regards,
Steve.
On 10/15/2014 12:32 PM, Lee wrote:
> You are correct. Can't think of any case where they add value commensurate
> with their cost.
>
> Lee
>
> -----Original Message-----
> From: Aaditya K
> Sent: Wednesday, October 15, 2014 10:41 AM
> To: si-list
> Subject: [SI-LIST] Ground vias around signal via
>
> Hello Experts,
> I have a question on ground vias placement around signal via.
>
> My opinion is, if we have a proper return path, they are not necessary. Am
> I correct?
>
> Any situations they are useful other than shielding?
>
> How will they help? When do we need them?
>
> Please help.
>
> Thanks
> Aaditya
>
>
> ------------------------------------------------------------------
> 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
>
>
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2014.0.4765 / Virus Database: 4040/8394 - Release Date: 10/15/14
>
> ------------------------------------------------------------------
> 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
>
>
>
--
Steve Weir
IPBLOX, LLC
1580 Grand Point Way
MS 34689
Reno, NV 89523-9998
www.ipblox.com
(775) 299-4236 Business
(866) 675-4630 Toll-free
(707) 780-1951 Fax
All contents Copyright (c)2013 IPBLOX, LLC. All Rights Reserved.
This e-mail may contain confidential material.
If you are not the intended recipient, please destroy all records
and notify the sender.
------------------------------------------------------------------
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:
