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[SI-LIST] Re: Routing Signals Between PWB Layers - Part 2
- From: Joel Brown <joel@xxxxxxxxxx>
- To: scott@xxxxxxxxxxxxx
- Date: Thu, 04 May 2006 10:25:22 -0700
Just curious. What is the approximate single user cost of those products?
Thanks - Joel
Scott McMorrow wrote:
> Sigrity Power SI and Ansoft SIWave will both do what you're looking for.
> Scott McMorrow
> Teraspeed Consulting Group LLC
> 121 North River Drive
> Narragansett, RI 02882
> (401) 284-1827 Business
> (401) 284-1840 Fax
>
> http://www.teraspeed.com
>
> Teraspeed® is the registered service mark of
> Teraspeed Consulting Group LLC
>
>
>
> Nima Lotfi wrote:
>
>> Istvan,
>>
>> I'm looking for a tool to simulate board resonance. Did you use
>> simulation software to confirm the frequency of modal resonance of the
>> PCB planes? If so can tell me what tool you've used.
>>
>> Thanks,=20
>> ______________________=20
>> Nima Lotfi, P. Eng=20
>> Digital Hardware Design Engineer=20
>> Nortel
>>
>>
>> 758-7786 ESN=20
>> (403) 769-7786 Direct=20
>> (403) 769-5350 Fax=20
>> LNima@xxxxxxxxxxxxxxxxxx=20
>>
>>
>>
>>
>>> -----Original Message-----
>>> From: si-list-bounce@xxxxxxxxxxxxx
>>>
>>>
>> [mailto:si-list-bounce@xxxxxxxxxxxxx]
>>
>>
>>> On Behalf Of Istvan Novak
>>> Sent: Thursday, May 04, 2006 7:10 AM
>>> To: GStokes@xxxxxxxxx
>>> Cc: SI-List
>>> Subject: [SI-LIST] Re: Routing Signals Between PWB Layers - Part 2
>>> =20
>>> Geoff, Doug,
>>> =20
>>> This example nicely shows the importance of proper power distribution
>>> design.
>>> =20
>>> The emission peaks correspond to the modal resonances of the PCB
>>>
>>>
>> planes.
>>
>>
>>> As Doug points out in the article, moving the planes closer would
>>>
>>>
>> reduce
>>
>>
>>> the
>>> emission about proportionally. However, if one wants to stay with a
>>> four-layer
>>> construction, reducing the plane separation is not a viable solution:
>>>
>>>
>> it
>>
>>
>>> would
>>> either result in an unmanageably thin board, or if we add the
>>>
>>>
>> tickhness
>>
>>
>>> back to
>>> the top/bottom dielectrics, in a dramatically reduced routing density.
>>> =20
>>> Nearby grounding vias would help, but in practical cases the two
>>>
>>>
>> planes
>>
>>
>>> are at
>>> different DC potentials, so it must be a bypass capacitor rather than
>>>
>>>
>> a
>>
>>
>>> stitching
>>> via. A single bypass capacitor will do little in the hundreds of MHz
>>> frequency range,
>>> even if it serves only one signal. Also, if we have wide busses
>>>
>>>
>> instead
>>
>>
>>> of a single
>>> trace, trying to provide a return path locally to all of the layer
>>> transitions becomes
>>> much harder to implement.
>>> =20
>>> A more realistic and straightforward solution is to design the
>>> power-distribution
>>> network in such a way that it does not exhibit large resonances. In
>>> multi-layer
>>> boards, where we may also have ground-ground planes creating such
>>> cavities, the
>>> solution is stitching vias, but not necessarily near the layer
>>> transitions. We would
>>> just need to make sure that the large resonating cavity is broken up
>>>
>>>
>> to
>>
>>
>>> sufficiently
>>> small blocks such that the lowest resonance frequency is safely above
>>> the highest
>>> frequency of excitation.
>>> =20
>>> Regards,
>>> =20
>>> Istvan Novak
>>> SUN Microsystems
>>> =20
>>> =20
>>> =20
>>> Geoff Stokes wrote:
>>> =20
>>>
>>>
>>>> Hi Doug
>>>>
>>>> In this experiment, you appear to have no plane vias adjacent to the
>>>> signal vias. What would happen if a few plane vias were added around
>>>> the transitions and fairly close by?
>>>>
>>>> Geoff Stokes
>>>> Systems Engineer
>>>> Zetex Semiconductors plc
>>>> Zetex Technology Park
>>>> Chadderton
>>>> Oldham
>>>> OL9 9LL
>>>> UK
>>>> =3D20
>>>> +44-161-622-4857
>>>> www.zetex.com
>>>> www.zetex.cn
>>>> =3D20
>>>>
>>>> =3D20
>>>> -----Original Message-----
>>>> From: si-list-bounce@xxxxxxxxxxxxx
>>>>
>>>>
>> [mailto:si-list-bounce@xxxxxxxxxxxxx]
>>
>>
>>>> On Behalf Of Doug Smith
>>>> Sent: 03 May 2006 21:41
>>>> To: SI-List
>>>> Subject: [SI-LIST] Routing Signals Between PWB Layers - Part 2
>>>>
>>>> Hi All,
>>>>
>>>> I have been writing and recording again and have posted part 2 of
>>>>
>>>>
>> my=3D20
>>
>>
>>>> article on signals that change layers in a PWB.
>>>>
>>>> Abstract: Printed wiring board, PWB, signal paths must often
>>>>
>>>>
>> change=3D20
>>
>>
>>>> layers in a board stackup. Under some conditions this can cause=3D20
>>>> problems. An emissions example is used to illustrate the
>>>>
>>>>
>> conditions=3D20
>>
>>
>>>> where changing layers can cause problems.
>>>>
>>>> The link to the article is the picture of the emissions plot at
>>>>
>>>>
>> the=3D20
>>
>>
>>>> bottom of the home page at http://emcesd.com .
>>>>
>>>> There is also an audio discussion of this article on my podcast
>>>>
>>>>
>> site:=3D20
>>
>>
>>>> http://emcesd-podcast.com where the direct link to the article is:
>>>>
>>>> http://emcesd-podcast.com/2006/may/2006-0503.mp3
>>>>
>>>> Can't download mp3 files? Download the following instead:
>>>>
>>>> http://emcesd-podcast.com/2006/may/2006-0503.dcs
>>>>
>>>> After download, change the extension from .dcs to .mp3 and the
>>>>
>>>>
>> file=3D20
>>
>>
>>>> will then be able to play on most computers. Since the last =
>>>>
>>>>
>> HFNews=3D20
>>
>>
>>>> there have been two new podcasts posted.
>>>>
>>>> Doug
>>>> --=3D20
>>>> -------------------------------------------------------
>>>> ___ _ Doug Smith
>>>> \ / ) P.O. Box 1457
>>>> =3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D Los =
>>>>
>>>>
>> Gatos, CA 95031-1457
>>
>>
>>>> _ / \ / \ _ TEL/FAX: 408-356-4186/358-3799
>>>> / /\ \ ] / /\ \ Mobile: 408-858-4528
>>>> | q-----( ) | o | Email: doug@xxxxxxxxxx
>>>> \ _ / ] \ _ / Website: http://www.dsmith.org
>>>> -------------------------------------------------------
>>>>
>>>>
>>>>
>>>>
>>>>
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