[SI-LIST] Re: Need technical ammunition for switching to singleground plane !

Orin,

You don't make our profession sound all that professional!  Not something
to be very proud of.  Maybe we should be working on raising the bad.  That
often means educating our management on what right looks like.

Lee  


> [Original Message]
> From: <olaney@xxxxxxxx>
> To: <leeritchey@xxxxxxxxxxxxx>
> Cc: <istvan.novak@xxxxxxxxxxx>; <si-list@xxxxxxxxxxxxx>
> Date: 9/22/2007 3:46:44 PM
> Subject: Re: [SI-LIST] Re: Need technical ammunition for switching to
singleground plane !
>
>  
> On Sat, 22 Sep 2007 15:24:07 -0700 "Lee Ritchey"
> <leeritchey@xxxxxxxxxxxxx> writes:
> > Istvan,
> > 
> (middle deleted)
>
> > Shouldn't an EE be expected to be as thorough in his design analysis 
> > as the
> > structural engineers who design bridges?  We punish them if their 
> > bridges
> > fall in the water, don't we?
> > 
> > Lee
>
> Bridge designers must have professional engineering licenses by law, and
> to get that must pass a licensing examination as a putative guarantee of
> competence.  That is because their products must be used by persons not
> qualified to judge the design worthiness of the structures they must use,
> and because the consequences of failure can be catastrophic.  For the
> same reasons, equivalent licensing is a requirement for doctors and
> lawyers.
>
> Here, the EE is presumably working in an organization that has some
> expertise to judge the design work, and the worst consequence of screwing
> up is a missed marketing window and getting laid off or fired.  No
> license is required -- and sometimes not even a degree.  Many employers
> aim for someone good enough to do the work, but no so good that they are
> expensive or likely to get bored and leave.  Likewise the tools provided
> are likely to be "good enough" rather than best in class.  And paying for
> training?  Go read the manual.  Or email the SI list...
>
> Orin
>
> > 
> > 
> > > [Original Message]
> > > From: Istvan Novak <istvan.novak@xxxxxxxxxxx>
> > > To: <leeritchey@xxxxxxxxxxxxx>
> > > Cc: Gilles Aminot <gilles.aminot@xxxxxxxxxxxxxxx>; 
> > <si-list@xxxxxxxxxxxxx>
> > > Date: 9/22/2007 3:09:29 PM
> > > Subject: Re: [SI-LIST] Re: Need technical ammunition for switching 
> > to
> > singleground plane !
> > >
> > > Lee,
> > >
> > > I like and agree with your approach in principle, and whenever 
> > > circumstances allow, this is
> > > the proper way of solving things.  I think, however, the question 
> > is 
> > > triggered by situations,
> > > when life does not allow us to follow this procedure.  Unless 
> > there is 
> > > data available from
> > > the past (and this is what the question was looking for) either by 
> > the 
> > > person facing the
> > > problem (meaning that the person had the time and resources to do 
> > the 
> > > detailed homework
> > > before the question came up) of from other sources, like 
> > publications, 
> > > SI-LIST, etc,
> > > answering all (or just a few) of these  five questions, would take 
> > much 
> > > longer than what is
> > > allowed by a typical project cycle.
> > >
> > > Regards,
> > >
> > > Istvan Novak
> > > SUN Microsystems
> > >
> > > Lee Ritchey wrote:
> > > > Gilles,
> > > >
> > > > I understand how difficult it is to find articles on this topic.
> > > >
> > > > Perhaps it is fair to turn the question around for those adamant 
> > about
> > > > splitting grounds.
> > > >
> > > > The proponents of this practice need to answer these questions 
> > for you.
> > > >
> > > > 1. Is there a problem that needs to be solved?
> > > > 2. What, exactly is the problem?
> > > > 3. Does the proposed solution solve the problem?
> > > > 4. Does the proposed solution not create any new problems?
> > > > 5. Is there no better solution?
> > > >
> > > > In almost all cases, things stop at 1, becasue the proponents of 
> > this
> > > > practice are solving an imaginary problem.
> > > >
> > > > Lee
> > > >
> > > >
> > > >   
> > > >> [Original Message]
> > > >> From: Gilles Aminot <gilles.aminot@xxxxxxxxxxxxxxx>
> > > >> To: <si-list@xxxxxxxxxxxxx>
> > > >> Date: 9/21/2007 2:39:55 PM
> > > >> Subject: [SI-LIST] Need technical ammunition for switching to 
> > single
> > > >>     
> > > > ground plane !
> > > >   
> > > >> Hi Everyone,
> > > >>  
> > > >> I'm working on a new design and would like to eliminate split 
> > ground
> > > >> planes. In the past we've always split the analog ground plane 
> > (for
> > > >> analog audio circuits and codecs) and joined it at one location
> > > >> (sometimes shorting or through an inductor). I've read lot's of
> > postings
> > > >> on this group explaining good reasons not to split ground 
> > planes, but
> > > >> the only real supporting documentation I have seen is the 
> > following
> > > >> article: 
> > > >> 
> > http://www.analog.com/analog_root/static/pdf/raq/RAQ_groundingADCs.pdf
> > > >>
> >
> <http://www.analog.com/analog_root/static/pdf/raq/RAQ_groundingADCs.pdf>
> > > >> and it does not provide much depth..
> > > >>  
> > > >> I have been meeting some resistance to eliminating the split 
> > ground
> > > >> planes and I am looking for technical articles showing the 
> > advantages
> > of
> > > >> using a single ground plane in designs with mixed high speed 
> > digital
> > and
> > > >> sensitve analog circuits. I keep bumping my head against 
> > datasheets or
> > > >> articles that say analog & digital grounds should be separated 
> > (such
> > as:
> > > >> http://www.ultracad.com/articles/planesplits.pdf), which makes 
> > it
> > > >> difficult to convince my peers that changing our approach is 
> > the way to
> > > >> go. Can anyone share or point me to articles which may help me 
> > plead my
> > > >> case. I would also appreciate if anyone could share some real 
> > life
> > > >> experiences of going from split to single ground plane.
> > > >>  
> > > >> Kindest Regards,
> > > >> Gilles Aminot, P.Eng
> > > >> Hardware Design Engineer
> > > >>  
> > > >> Librestream Technologies Inc
> > > >> Unit 200 - 55 Rothwell Rd
> > > >> Winnipeg MB. Canada
> > > >> R3P-2M5
> > > >> PH: 204-487-0612 Ext 218
> > > >> FX: 204-487-0914
> > > >>  
> > > >>
> > > >>     
> > 
> > 
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> > 
> > 
> > 
>  


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