[SI-LIST] Re: Question about split gnd planes
- From: "Lee Ritchey" <leeritchey@xxxxxxxxxxxxx>
- To: "Ayan Bhattacharyya" <ayan_bhattacharyya@xxxxxxxxxxxx>, weirsi@xxxxxxxxxx, "Manickavelu M." <manickavelu_m@xxxxxxxxxxxx>, istvan.novak@xxxxxxxxxxx, "Ed Troy" <etroy@xxxxxxxxxxxxxxx>, si-list@xxxxxxxxxxxxx
- Date: Fri, 26 May 2006 09:31:23 -0700
I'm not sure where the notion came from that there should be an AGNDand a
DGND in a PCB. It's not true. I've attached a short piece written by the
technical specialist from Analog Devices stating just this.
> [Original Message]
> From: Ayan Bhattacharyya <ayan_bhattacharyya@xxxxxxxxxxxx>
> To: <weirsi@xxxxxxxxxx>; Manickavelu M. <manickavelu_m@xxxxxxxxxxxx>;
<istvan.novak@xxxxxxxxxxx>; Ed Troy <etroy@xxxxxxxxxxxxxxx>;
<si-list@xxxxxxxxxxxxx>
> Date: 5/26/2006 3:03:02 PM
> Subject: [SI-LIST] Re: Question about split gnd planes
>
> Hi,
> As per I know no tool will allow you to connect the AGND and DGND
> directly....u can connect them through CAPs also...
> Else in same ground plane u can maintain less noise interference by making
> bottle-necks in the layout for the different noise sources.
> "Istvan Novak"'s approach is a good one...ground guard signals also help a
> lot ...specially for clock signals...around crystals.
> Regards
> Ayan Bhattacharyya.
>
>
> -----Original Message-----
> From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
On
> Behalf Of steve weir
> Sent: Friday, May 26, 2006 4:47 PM
> To: Manickavelu M.; istvan.novak@xxxxxxxxxxx; Ed Troy;
si-list@xxxxxxxxxxxxx
> Subject: [SI-LIST] Re: Question about split gnd planes
>
> Manix, no. There are many misconceptions out there about the myth of
> ground and its relation to noise isolation. Those myths get
> propagated into misguided applications of moats and such. Think in
> fields and the misconceptions go away.
>
> Steve.
> At 09:50 PM 5/25/2006, Manickavelu M. wrote:
> >Istan,
> >Is it not that the analog and digital grounds planes can not be connected
> >together anywhere but only under the chip that sources the analog
signals?
> >Also that while coupling these two planes we should not use direct Cu
plane
> >connection but couple them via inductors?
> >
> >Manix,
> >MindTree.
> >
> >-----Original Message-----
> >From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
On
> >Behalf Of istvan.novak@xxxxxxxxxxx
> >Sent: Friday, May 26, 2006 6:26 AM
> >To: Ed Troy; si-list@xxxxxxxxxxxxx
> >Subject: [SI-LIST] Re: Question about split gnd planes
> >
> >Ed,
> >
> >Splitting more than one ground plane in the stackup requires a lot of
> >consideration, and mostly it is not necessary. Isolating a sensitive
> circuit
> >(e.g., analog input, low-jitter oscillator) may be a good idea, but
instead
> >of cutting a large solid ground plane, you may want to try first to put
the
> >circuit to be isolated on a grounded patch on a 'non-ground' layer. You
can
> >make ground surface patches under and around your circuit to be
isolated, or
> >you can put the patch on a signal layer.
> >
> >Regards,
> >
> >Istvan Novak
> >SUN Microsystems
> >
> >
> >From: Ed Troy <etroy@xxxxxxxxxxxxxxx>
> >Date: Thu May 25 15:38:33 CDT 2006
> >To: si-list@xxxxxxxxxxxxx
> >Subject: [SI-LIST] Question about split gnd planes
> >
> >If you have a circuit board that requires a split gnd plane over a
> >small section of the board, and you have several ground planes,
> >should only one have the split (the one nearest the side containing
> >the components that require analog ground) while the rest of the
> >ground planes are continuous, or should the split section be on all
> >ground layers? I would think that you should only have it on one
> >layer. Also, if it should only be on one layer, I would imagine it
> >would be best to connect it to the digital ground with one, and only
> >one, via. Is that generally correct? What are some good references
> >for layer stackups, etc? I know I saw one, once, but can't remember
where.
> >
> >Ed
> >
> >
> >------------------------------------------------------------------
> >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
> >
> >
> >------------------------------------------------------------------
> >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
> >
> >
> >
> >-- Attached file included as plaintext by Ecartis --
> >-- File: disclaimer.txt
> >
>
>---------------------------------------------------------------------------
-
> -------------------------------------------------
> >Disclaimer
>
>---------------------------------------------------------------------------
-
> -------------------------------------------------
> >
> >"This message(including attachment if any)is confidential and may be
> >privileged.Before opening attachments please check them
> >for viruses and defects.MindTree Consulting Private Limited
> >(MindTree)will not be responsible for any viruses or defects or
> >any forwarded attachments emanating either from within MindTree or
> >outside.If you have received this message by mistake please notify
> >the sender by return e-mail and delete this message from your
> >system. Any unauthorized use or dissemination of this message in
> >whole or in part is strictly prohibited. Please note that e-mails
> >are susceptible to change and MindTree shall not be liable for any
> >improper, untimely or incomplete transmission."
> >
>
>---------------------------------------------------------------------------
-
> -------------------------------------------------
> >
> >------------------------------------------------------------------
> >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
> >
>
> ------------------------------------------------------------------
> 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
>
>
>
> -- Attached file included as plaintext by Ecartis --
> -- File: disclaimer.txt
>
>
----------------------------------------------------------------------------
-------------------------------------------------
> Disclaimer
>
----------------------------------------------------------------------------
-------------------------------------------------
>
> "This message(including attachment if any)is confidential and may be
privileged.Before opening attachments please check them
> for viruses and defects.MindTree Consulting Private Limited
(MindTree)will not be responsible for any viruses or defects or
> any forwarded attachments emanating either from within MindTree or
outside.If you have received this message by mistake please notify the
sender by return e-mail and delete this message from your system. Any
unauthorized use or dissemination of this message in whole or in part is
strictly prohibited. Please note that e-mails are susceptible to change
and MindTree shall not be liable for any improper, untimely or incomplete
transmission."
>
>
----------------------------------------------------------------------------
-------------------------------------------------
>
> ------------------------------------------------------------------
> 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
>
-- Binary/unsupported file stripped by Ecartis --
-- Type: image/jpeg
-- File: AnalogDigitalGround.jpg
-- Desc: AnalogDigitalGround.jpg
------------------------------------------------------------------
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:
