[SI-LIST] Re: AC series capacitor position in high speeddifferential signals
- From: steve weir <weirsi@xxxxxxxxxx>
- To: "Peterson, James F (EHCOE)" <james.f.peterson@xxxxxxxxxxxxx>
- Date: Thu, 13 May 2010 10:56:59 -0700
I think the need for confirmation comes down to: What is the cost of
failure? What is the likelihood of failure if a measure is not taken?
Best Regards,
Steve.
Peterson, James F (EHCOE) wrote:
> You need all three to align : theory (what we expect to see),
> simulation, and measurement. It is only then that we can proceed
> confidently into production. (I'm borrowing heavily from a DesignCon
> panel discussion several years ago.)
>
> But we have to apply some engineering judgment to this approach. If
> we're not trail-blazing, we have good design margin and good models,
> maybe we can proceed without breadboarding. But if we are tight on
> margin, it's a new technology, and our company's crown jewels are at
> stake, then we need to make sure all three agree...
>
> Regard,
> Jim Peterson
> Honeywell
>
> -----Original Message-----
> From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
> On Behalf Of Lee Ritchey
> Sent: Thursday, May 13, 2010 1:25 PM
> To: Muranyi, Arpad; si-list@xxxxxxxxxxxxx
> Subject: [SI-LIST] Re: AC series capacitor position in high
> speeddifferential signals
>
> I don't trust either if they don't agree.
>
>
>
>> [Original Message]
>> From: Muranyi, Arpad <Arpad_Muranyi@xxxxxxxxxx>
>> To: <si-list@xxxxxxxxxxxxx>
>> Date: 5/13/2010 10:09:45 AM
>> Subject: [SI-LIST] Re: AC series capacitor position in high
>>
> speeddifferential signals
>
>> Hmmm... I wonder how many of us trusts their measurements
>> (blindly) without validating those? We all know that
>> probing will have an effect on the results, especially at
>> high speeds, right? Should I continue?
>>
>> Arpad
>> =============================================================
>>
>> -----Original Message-----
>> From: si-list-bounce@xxxxxxxxxxxxx
>>
> [mailto:si-list-bounce@xxxxxxxxxxxxx]
>
>> On Behalf Of Lee Ritchey
>> Sent: Thursday, May 13, 2010 11:28 AM
>> To: Istvan Novak
>> Cc: fei xue; si-list@xxxxxxxxxxxxx
>> Subject: [SI-LIST] Re: AC series capacitor position in high
>> speeddifferential signals
>>
>> I would maintain from my measurements that the reflections are
>> negligibly
>> small.
>>
>> I would also maintain that simulation results, no matter what the tool
>> or
>> operator, should not be trusted until they are validated by
>>
> measurements
>
>> to
>> insure the modelling is accurate. I've seen too many simulations done
>> incorrectly which were used to develop design rules that were either
>> ineffective or caused problems that I, for one, will not use the
>>
> results
>
>> of
>> unvalidated simulations.
>>
>> Each engineer can make up his or her own mind on this, but my
>>
> experience
>
>> says validate simulation results before betting any money on them.
>>
>> I'm not trying to offend anyone who does simulations, just advising
>> proceed
>> with caution.
>>
>> Lee
>>
>>
>>
>>> [Original Message]
>>> From: Istvan Novak <istvan.novak@xxxxxxx>
>>> To: Lee Ritchey <leeritchey@xxxxxxxxxxxxx>
>>> Cc: fei xue <harrison_cls@xxxxxxxxxxxx>; <si-list@xxxxxxxxxxxxx>
>>> Date: 5/12/2010 8:55:32 PM
>>> Subject: Re: [SI-LIST] Re: AC series capacitor position in high
>>>
>> speeddifferential signals
>>
>>> Lee,
>>>
>>> As it was pointed out in earlier threads, location does make a
>>> difference unless reflections are
>>> negligibly small. Assuming linearity, when we move components
>>>
> around,
>
>>> reciprocity prevails,
>>> but voltage transfer function from source to load will change, which
>>>
>> in
>>
>>> turn impacts eye
>>> parameters.
>>>
>>> Regards,
>>>
>>> Istvan Novak
>>> Oracle-America
>>>
>>>
>>> Lee Ritchey wrote:
>>>
>>>> This has been answered before on this forum. Since the circuits
>>>>
> are
>
>>>> linear, it does not matter from a signal integrity point of view.
>>>>
>>>> Lee
>>>>
>>>>
>>>>
>>>>
>>>>> [Original Message]
>>>>> From: fei xue <harrison_cls@xxxxxxxxxxxx>
>>>>> To: <si-list@xxxxxxxxxxxxx>
>>>>> Date: 5/12/2010 11:35:49 AM
>>>>> Subject: [SI-LIST] AC series capacitor position in high speed
>>>>>
>>>>>
>>>> differential signals
>>>>
>>>>
>>>>> Hello all,
>>>>> We often can get different guideline of placing capacitor
>>>>>
> position
>
>> when
>>
>>>>>
>>>>>
>>>> placing AC series capacitor on high speed differential signals,
>>>>
> like
>
>> PCIe,
>>
>>>> SAS or LVDS signals. sometimes we followed the guideline to put
>>>>
>> capacitors
>>
>>>> near driver, sometimes near multi-connection connectors or
>>>>
> sometimes
>
>> put it
>>
>>>> near receivers.
>>>>
>>>>
>>>>> Could anybody tell me what is the consideration of capacitor
>>>>>
>> placing
>>
>>>>>
>>>>>
>>>> position? Thanks!
>>>>
>>>>
>>>>> Harrison
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>> ------------------------------------------------------------------
>> 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.net
>>
>> 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
>>
>>
>> ------------------------------------------------------------------
>> 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.net
>>
>> 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
>>
>>
>
>
> ------------------------------------------------------------------
> 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.net
>
> 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
>
>
> ------------------------------------------------------------------
> 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.net
>
> 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
150 N. Center St. #211
Reno, NV 89501
www.ipblox.com
(775) 299-4236 Business
(866) 675-4630 Toll-free
(707) 780-1951 Fax
------------------------------------------------------------------
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.net
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:
