[SI-LIST] Re: PCB STACKUP
- From: Vinu Arumugham <vinu@xxxxxxxxx>
- To: clandrum@xxxxxxxxx
- Date: Thu, 22 Jan 2004 11:14:11 -0800
The disadvantage is that at every transition (package<->board,
connectors and signal vias), one will have to provide return paths for
both AGND and POWER_ANALOG. So, using only AGND as the reference would
make it easier to provide return paths and avoid impedance discontinuities.
Thanks,
Vinu
Chris Landrum x311 wrote:
>I see no advantage...
>-----Original Message-----
>From: Vinu Arumugham [mailto:vinu@xxxxxxxxx]
>Sent: Wednesday, January 21, 2004 5:44 PM
>To: 'Nosovitski, Alexander (Contr)'
>Cc: clandrum@xxxxxxxxx; 'si-list@xxxxxxxxxxxxx'
>Subject: Re: [SI-LIST] Re: PCB STACKUP
>
>
>What's the advantage (other than layer count) of routing DIFF_SIGNAL
>referenced to AGND and POWER_ANALOG instead of using a single stripline
>referenced to two GND or AGND planes?
>
>Thanks,
>Vinu
>
>Chris Landrum x311 wrote:
>
>
>Alexander,
>
>
>
>I would be inclined to say you do not need the AGND planes. Without knowing
>
>the intricate parts of your design, I would say that tying AGND and GND
>
>together at a backplane will be a BAD idea. With the information at hand, I
>
>would assume you are using the AGND to somehow "benefit" the Gb/s signals.
>
>I would argue, that if this is the case, and you tie the AGND to GND
>
>together at the backplane, you could easily hurt the design especially from
>
>an EMI perspective, as you may induce loop currents.
>
>
>
>On another note, tt looks like you have good inner-planar capacitance built
>
>into the design....which is good. I would suggest that you make sure you
>
>have built this capacitance for all the power supplies in your design.
>
>Also, I notice that there are many PWR/GND plane pairs towards the center of
>
>the board. If you intend these structures (the ones toward the middle
>
>layers) to provide inner planar capacitance, I might argue that the
>
>inductance of the vias used to attach the planes may be great enough to
>
>offset the benefit of the inner-planar capacitor. As such, you may be able
>
>to get rid of some of the internal planes to save cost. Now, if you have
>
>current or voltage requirements that require this many planes, then by all
>
>means, what you have designed is correct.
>
>
>
>Just my thoughts...for what they are worth.
>
>
>
>-----Original Message-----
>
>From: Nosovitski, Alexander (Contr)
>
>[ mailto:alexander.nosovitski@xxxxxxx <mailto:alexander.nosovitski@xxxxxxx>
>]
>
>Sent: Wednesday, January 21, 2004 4:44 PM
>
>To: 'Chris Landrum x311'
>
>Subject: RE: [SI-LIST] PCB STACKUP
>
>
>
>
>
>Hi Chris,
>
>
>
>Yes, AGND and GND will be tied together.
>
>I am not sure yet if it is going to be at the backplane or
>
>at the board.
>
>
>
>Regards,
>
>
>
>Alexander
>
>
>
>
>
>
>
>-----Original Message-----
>
>From: Chris Landrum x311 [ mailto:clandrum@xxxxxxxxx
><mailto:clandrum@xxxxxxxxx> ]
>
>Sent: Wednesday, January 21, 2004 4:18 PM
>
>To: Nosovitski, Alexander (Contr); si-list@xxxxxxxxxxxxx
><mailto:si-list@xxxxxxxxxxxxx>
>
>Subject: RE: [SI-LIST] PCB STACKUP
>
>
>
>
>
>The first thing that pops out to me is whether or not the AGND and GND
>
>layers will all be tied together. If not, then what is the purpose of the
>
>AGND layers?
>
>
>
>-----Original Message-----
>
>From: Nosovitski, Alexander (Contr)
>
>[ mailto:alexander.nosovitski@xxxxxxx <mailto:alexander.nosovitski@xxxxxxx>
>]
>
>Sent: Wednesday, January 21, 2004 4:03 PM
>
>To: si-list@xxxxxxxxxxxxx <mailto:si-list@xxxxxxxxxxxxx>
>
>Subject: [SI-LIST] PCB STACKUP
>
>
>
>
>
>Hello si-list,
>
>
>
>
>
>The design I am working on has a dense placement.
>
>
>
>The proposed stack up looks as follow:
>
>
>
>TOP
>
>POWER_ANALOG
>
>DIFF_SIGNAL (Gb/s signals)
>
>AGND
>
>
>
>GND
>
>POWER
>
>S
>
>S
>
>GND
>
>POWER
>
>S
>
>S
>
>GND
>
>SPLIT_POWER
>
>GND
>
>S
>
>S
>
>POWER
>
>GND
>
>S
>
>S
>
>GND
>
>
>
>AGND
>
>DIFF_SIGNAL_ANALOG (Gb/s signals)
>
>POWER ANALOG
>
>
>
>BOTTOM
>
>
>
>
>
>
>
>All signal layers are 0.5 Oz copper and
>
>
>
>All planes are solid ( except one in the middle) with 0.5 Oz copper.
>
>
>
>The diff. signals are running at 2.5Gb/s.
>
>
>
>
>
>There are different opinions about analog plane location.
>
>
>
>Could the arrangement above cause a problem?
>
>
>
>What else should I be concern about?
>
>
>
>
>
>
>
>Any help or suggestion is appreciated!
>
>
>
>
>
>Regards,
>
>
>
>Alexander Nosovitski
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>-----Original Message-----
>
>From: Salkow, Steven [ mailto:steven.salkow@xxxxxxxx
><mailto:steven.salkow@xxxxxxxx> ]
>
>Sent: Wednesday, January 21, 2004 1:57 PM
>
>To: weirsp@xxxxxxxxxx <mailto:weirsp@xxxxxxxxxx> ; fred@xxxxxxxxxxxxx
><mailto:fred@xxxxxxxxxxxxx> ; kar_thik_v1@xxxxxxxxx
><mailto:kar_thik_v1@xxxxxxxxx>
>
>Cc: si-list@xxxxxxxxxxxxx <mailto:si-list@xxxxxxxxxxxxx>
>
>Subject: [SI-LIST] Re: Looking for thin dielectric tape
>
>
>
>
>
>4 mil prepreg (pcb laminate) is generally available from anyone doing
>
>multilayer PCB. You may also get samples from laminate vendors (dupont,
>
>Norplex) (sprayed with Scotch 444 adhesive for cold adhesion to copper
>
>foils)
>
>3M (tape division) have exactly what your looking for up to 36" wide
>
>slit to any width but they have minimum qtys
>
>
>
>see
>
>http://products3.3m.com/catalog/us/en001/utilities_telecom/oem_electrica
><http://products3.3m.com/catalog/us/en001/utilities_telecom/oem_electrica>
>
>l/node_R5MTBSFVGPbe/root_GST1T4S9TCgv/vroot_GSHBRQT7DVge/gvel_BBGZX3B1QG
>
>gl/theme_us_oemeletrical_3_0/command_AbcPageHandler/output_html
>
>
>
>Catalog on the above page for download
>
>
>
>Steve Salkow
>
>Lockheed Martin
>
>3200 Zanker Road
>
>San Jose, CA 95134
>
>(408) 473-4058 (san Jose)
>
>(408) 742-4162 (Sunnyvale)
>
>steven.salkow@xxxxxxxx <mailto:steven.salkow@xxxxxxxx>
>
>salkow@xxxxxxxxxxxx <mailto:salkow@xxxxxxxxxxxx>
>
>(925) 462-1075 Home
>
>(925-) 487-5946 Cell
>
>(408) 468-7271 Numeric Pager
>
>
>
>-----Original Message-----
>
>From: si-list-bounce@xxxxxxxxxxxxx <mailto:si-list-bounce@xxxxxxxxxxxxx>
>
>[ mailto:si-list-bounce@xxxxxxxxxxxxx <mailto:si-list-bounce@xxxxxxxxxxxxx>
>]On Behalf Of steve weir
>
>Sent: Tuesday, January 20, 2004 11:17 PM
>
>To: fred@xxxxxxxxxxxxx <mailto:fred@xxxxxxxxxxxxx> ; kar_thik_v1@xxxxxxxxx
><mailto:kar_thik_v1@xxxxxxxxx>
>
>Cc: si-list@xxxxxxxxxxxxx <mailto:si-list@xxxxxxxxxxxxx>
>
>Subject: [SI-LIST] Re: Looking for thin dielectric tape
>
>
>
>
>
>If you want to lay out a board, onesy, twosy, Express PCB is not a bad
>
>way
>
>to go. www.expresspcb.com <http://www.expresspcb.com> It sure beats the
>Bishop Graphics adhesive
>
>backed Cu tape, or a bathroom full of ferric chloride.
>
>
>
>Steve.
>
>At 01:44 PM 1/20/2004 -0800, Fred Townsend wrote:
>
>
>
>The last time I check you could still get mylar sheeting at most
>
>drafting and staionary stores. You would to apply your own adhesive.
>
>Comes in 4 and 7 mil thicknesses. You can also get polyester sheeting
>
>frosted one side and adhesive on the other for making labels. Failing
>
>that how about 3M's double sticky magic tape?
>
>
>
>Fred Townsend
>
>
>
>Karthik V wrote:
>
>
>
>
>
>Hello,
>
>
>
> I am a student at the State University of New York. I am
>
>
>
>looking for a double sided sticky dielectric tape (more like a sheet )
>
>
>
>of
>
>
>
>thickness about 4mils (0.1mm) and with a dielectric constant of
>
>around 4, to use between copper sheets - to make a "temporary board".
>
>
>
>I
>
>
>
>tried things like epoxy, but it's almost impossible to get it so thin
>
>
>
>and
>
>
>
>still provide infinite DC resistance.
>
>
>
> Could anyone point me to places where I could look for this
>
>
>
>
>
>
>
>kind of stuff. Is there anything else I could try to get the
>
>
>
>dielectric
>
>
>
>(with Dk around 4) so thin ( apart from elaborate processes ) .
>
>
>
>thanks in advance,
>
>Karthik,
>
>
>
>---------------------------------
>
>Do you Yahoo!?
>
>Yahoo! Hotjobs: Enter the "Signing Bonus" Sweepstakes
>
>
>
>------------------------------------------------------------------
>
>To unsubscribe from si-list:
>
>si-list-request@xxxxxxxxxxxxx <mailto: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
><//www.freelists.org/webpage/si-list>
>
>
>
>For help:
>
>si-list-request@xxxxxxxxxxxxx <mailto:si-list-request@xxxxxxxxxxxxx> with
>'help' in the Subject field
>
>
>
>List technical documents are available at:
>
> http://www.si-list.org <http://www.si-list.org>
>
>
>
>List archives are viewable at:
>
> //www.freelists.org/archives/si-list
><//www.freelists.org/archives/si-list>
>
>or at our remote archives:
>
> http://groups.yahoo.com/group/si-list/messages
><http://groups.yahoo.com/group/si-list/messages>
>
>Old (prior to June 6, 2001) list archives are viewable at:
>
> http://www.qsl.net/wb6tpu <http://www.qsl.net/wb6tpu>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>------------------------------------------------------------------
>
>To unsubscribe from si-list:
>
>si-list-request@xxxxxxxxxxxxx <mailto: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
><//www.freelists.org/webpage/si-list>
>
>
>
>For help:
>
>si-list-request@xxxxxxxxxxxxx <mailto:si-list-request@xxxxxxxxxxxxx> with
>'help' in the Subject field
>
>
>
>List technical documents are available at:
>
> http://www.si-list.org <http://www.si-list.org>
>
>
>
>List archives are viewable at:
>
> //www.freelists.org/archives/si-list
><//www.freelists.org/archives/si-list>
>
>or at our remote archives:
>
> http://groups.yahoo.com/group/si-list/messages
><http://groups.yahoo.com/group/si-list/messages>
>
>Old (prior to June 6, 2001) list archives are viewable at:
>
> http://www.qsl.net/wb6tpu <http://www.qsl.net/wb6tpu>
>
>
>
>
>
>
>
>
>
>------------------------------------------------------------------
>
>To unsubscribe from si-list:
>
>si-list-request@xxxxxxxxxxxxx <mailto: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
><//www.freelists.org/webpage/si-list>
>
>
>
>For help:
>
>si-list-request@xxxxxxxxxxxxx <mailto:si-list-request@xxxxxxxxxxxxx> with
>'help' in the Subject field
>
>
>
>List technical documents are available at:
>
> http://www.si-list.org <http://www.si-list.org>
>
>
>
>List archives are viewable at:
>
> //www.freelists.org/archives/si-list
><//www.freelists.org/archives/si-list>
>
>or at our remote archives:
>
> http://groups.yahoo.com/group/si-list/messages
><http://groups.yahoo.com/group/si-list/messages>
>
>Old (prior to June 6, 2001) list archives are viewable at:
>
> http://www.qsl.net/wb6tpu <http://www.qsl.net/wb6tpu>
>
>
>
>
>
>------------------------------------------------------------------
>
>To unsubscribe from si-list:
>
>si-list-request@xxxxxxxxxxxxx <mailto: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
><//www.freelists.org/webpage/si-list>
>
>
>
>For help:
>
>si-list-request@xxxxxxxxxxxxx <mailto:si-list-request@xxxxxxxxxxxxx> with
>'help' in the Subject field
>
>
>
>List technical documents are available at:
>
> http://www.si-list.org <http://www.si-list.org>
>
>
>
>List archives are viewable at:
>
> //www.freelists.org/archives/si-list
><//www.freelists.org/archives/si-list>
>
>or at our remote archives:
>
> http://groups.yahoo.com/group/si-list/messages
><http://groups.yahoo.com/group/si-list/messages>
>
>Old (prior to June 6, 2001) list archives are viewable at:
>
> http://www.qsl.net/wb6tpu <http://www.qsl.net/wb6tpu>
>
>
>
>------------------------------------------------------------------
>
>To unsubscribe from si-list:
>
>si-list-request@xxxxxxxxxxxxx <mailto: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
><//www.freelists.org/webpage/si-list>
>
>
>
>For help:
>
>si-list-request@xxxxxxxxxxxxx <mailto:si-list-request@xxxxxxxxxxxxx> with
>'help' in the Subject field
>
>
>
>List technical documents are available at:
>
> http://www.si-list.org <http://www.si-list.org>
>
>
>
>List archives are viewable at:
>
> //www.freelists.org/archives/si-list
><//www.freelists.org/archives/si-list>
>
>or at our remote archives:
>
> http://groups.yahoo.com/group/si-list/messages
><http://groups.yahoo.com/group/si-list/messages>
>
>Old (prior to June 6, 2001) list archives are viewable at:
>
> http://www.qsl.net/wb6tpu <http://www.qsl.net/wb6tpu>
>
>
>
>------------------------------------------------------------------
>
>To unsubscribe from si-list:
>
>si-list-request@xxxxxxxxxxxxx <mailto: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
><//www.freelists.org/webpage/si-list>
>
>
>
>For help:
>
>si-list-request@xxxxxxxxxxxxx <mailto:si-list-request@xxxxxxxxxxxxx> with
>'help' in the Subject field
>
>
>
>List technical documents are available at:
>
> http://www.si-list.org <http://www.si-list.org>
>
>
>
>List archives are viewable at:
>
> //www.freelists.org/archives/si-list
><//www.freelists.org/archives/si-list>
>
>or at our remote archives:
>
> http://groups.yahoo.com/group/si-list/messages
><http://groups.yahoo.com/group/si-list/messages>
>
>Old (prior to June 6, 2001) list archives are viewable at:
>
> http://www.qsl.net/wb6tpu <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 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 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:
