[SI-LIST] Re: Split gnd planes - for/against? - Thanks!

Larry, yes it did come with the ChipQuake software.  ChipQuake is 
focused on the IC and while it does allow specifying the PCB bypass 
network and package power / ground connections it doesn't  not have that 
facility.  For small problems you could can model in the student version 
of Sphinx.

Steve.
simsonl@xxxxxxxxxxxxxx wrote:
> Steve,
>
> The book you mentioned in an earlier post, "Noise Coupling in Integrated 
> Circuits", is on amazon.com bundled with a simulation software.  Did you get 
> yours with that software and can it simulate multiple (split) power/ground 
> planes?
>
> Thanks
> Larry
>
>
> ---- steve weir <weirsi@xxxxxxxxxx> wrote: 
>   
>> Tony usually that is the right decision.  However, there are cases when 
>> a package will not fit and still provide adequate isolation between 
>> circuits without implementing a split.  These don't happen in digital 
>> designs running one signaling level. 
>>
>> But suppose that you have a big digital bus switching 5A / ns that is 
>> 0.25" away from some analog circuit that is sensitive to 10uV noise.  Do 
>> you think the 0.25" separation will be enough?  If you cannot change the 
>> placement to put the analog circuitry further away, what will you do?
>>
>> Steve.
>>
>> Tony Luan wrote:
>>     
>>> Hi Sol,
>>>
>>> I think to split GND plane is not a good idea. 
>>> For any high frequency noise, GND and power plane are playing completely
>>> equivalent role. How can a high frequency noise tell which plane is GND?
>>> Which plane is power? Why not split power plane instead and keep a solid
>>> complete GND plane, because in package or PCB, we have tons of power
>>> rails and power islands already. 
>>> The biggest disadvantage to split GND plane I saw is that it increases
>>> routing difficulty when try to avoid high speed signal, clock, parallel
>>> bus across those gaps on GND plane. 
>>>
>>> Thanks 
>>> Tony
>>> -----Original Message-----
>>> From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
>>> On Behalf Of Sol Tatlow
>>> Sent: Thursday, April 09, 2009 4:58 AM
>>> To: si-list@xxxxxxxxxxxxx
>>> Subject: [SI-LIST] Re: Split gnd planes - for/against? - Thanks!
>>>
>>> One last mail to put this thread 'to bed'...
>>>
>>> Thanks to everyone who took the time to reply, particularly to
>>> those who actually gave me what I asked for, those reluctant beasts,
>>> the real-life examples - it's great that you're willing to so fully
>>> participate in such a discussion. After all, theory is great;
>>> coupled with real-life examples it's even better.
>>>
>>> Of course, the specific examples can't be applied 1:1 to any other
>>> design, as has been said 'x' times, but I, for one, am nevertheless
>>> wiser for the experiences that have been shared... I believe I'm a
>>> good engineer, but won't stop learning 'till the day I die.
>>>
>>> It was also good to see that I am not the only one suffering at the
>>> hands of less-than-perfect datasheets and the implementation of
>>> often contradictoray 'hints' :) - regardless of simulation results
>>> and past experiences, it's not always easy when it comes to
>>> persuading a customer, who is still convinced that app notes are
>>> written by all-knowing beings, to 'do the right thing'.
>>>
>>> Sol
>>>
>>>   
>>>       
>> -- 
>> Steve Weir
>> Teraspeed Consulting Group LLC 
>> 121 North River Drive 
>> Narragansett, RI 02882 
>>
>> California office
>> (866) 675-4630 Business
>> (707) 780-1951 Fax
>>
>> Main office
>> (401) 284-1827 Business 
>> (401) 284-1840 Fax 
>>
>> Oregon office
>> (503) 430-1065 Business
>> (503) 430-1285 Fax
>>
>> http://www.teraspeed.com
>> This e-mail contains proprietary and confidential intellectual property of 
>> Teraspeed Consulting Group LLC
>> ------------------------------------------------------------------------------------------------------
>> Teraspeed(R) is the registered service mark of Teraspeed Consulting Group LLC
>>
>> ------------------------------------------------------------------
>> 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:
>> http://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:     
>>              http://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
>>   
>>
>>     
>
>
>   


-- 
Steve Weir
Teraspeed Consulting Group LLC 
121 North River Drive 
Narragansett, RI 02882 

California office
(866) 675-4630 Business
(707) 780-1951 Fax

Main office
(401) 284-1827 Business 
(401) 284-1840 Fax 

Oregon office
(503) 430-1065 Business
(503) 430-1285 Fax

http://www.teraspeed.com
This e-mail contains proprietary and confidential intellectual property of 
Teraspeed Consulting Group LLC
------------------------------------------------------------------------------------------------------
Teraspeed(R) is the registered service mark of Teraspeed Consulting Group LLC

------------------------------------------------------------------
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:
http://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:     
                http://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: