Why not just farm this out. The design houses we use build our substrates
for flip chip as well as large telecom and AP modules.
The simple stuff they shoot back to us in a day, the larger ones in 3 to 4.
Seems like it would save you time, your company money, and your reliability
people a lot of headaches.
----- Original Message -----
From: "Joseph Matthews" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, February 08, 2005 12:58 AM
Subject: Re: [DC] Designing PCB footprints
> Dear Mario, Everyone;
>
> Thanks for the feedback everyone. Thanks Mario. Understood, it'd be
impractical for me to think I could learn all of the nuiances of PCB design
and in being perfectly candid, I'm not about to -- there are too many
seasoned people out there...it makes no sense for me to embark down that
road at this stage in my carrer -- irrespective of how lucrative it might be
;) (trust me, hardware engineers aren't paid *that* much).
>
> No less, for simple, one or two day prototypes I need to be able to layout
my own boards. It's not practical to outsource hardware test boards
(Processor/Controller boards, FPGAs, CPLDs, etc -- literally 20-30
components, a few pull ups, bypass caps, etc., and usually one or two real
"interface" devices -- i.e. a header or two, comm. connector (RS-232, I2C),
power, etc.)
>
> The unfortunate thing is that I've gone down this road before and to-date
I've been able to get away with literally giving a schematic over to the
baord house and for pennies (ok, maybe not pennies, but cheap) they've gone
ahead and taken my schematic and a little chicken-scratch and put out a
board for me. Well, things are getting a bit more complicated that that and
our proto shop has had to change...long story short, I need to be able to
turn out something like a decent set of gerbers and though I fancy myself
pretty good at interpreting standards and information, thought who better to
ask than the experts (I too am aware of just how little I know sometimes,
beleive me).
>
> So I'm hoping that people have some tips, some basics, some fundamentals
that'll help me get started in making something farily reliable. I checked
with the board house and they are fine about specifying certain design
constraints, and as you'd expect, the datasheet gives you some more to go
with. The problem is that all the informaiton I can get from the fabricator
is not going to be enough to spare me the inevitable reject and I'm sure
(though you may hat e to admit it) you've seen years of mistakes that I'm
hoping to avoid. Any wisdom, insights, thoughts, prayers, would be
appreciated :)
>
> Sincerely,
>
> Joe
>
> Mario Irigoyen <[log in to unmask]> wrote:
> Hi all,
>
> Well, here we go. I guess that's why there are professional PCB
> designers who design circuit boards and there are hardware engineers who
> design circuits. I certainly wouldn't try to grasp (or even attempt to
> learn) all the caveats of hardware design so I certainly wouldn't expect
> an engineer to do the same for PCB design. Us PCB guys understand the
> processes, guidelines, rules ... because we deal with them every day. I
> feel for you. You are being asked (forced) to move out of your realm
> into uncharted territory for what, to save time, money? The reality is -
> neither. Engineers get paid more than PCB designers (if not true please
> correct me). So, even if you could design a board in the same time as a
> PCB designer the cost is higher. But that won't happen. Then there are
> all of the manufacturing, testing, reliability ... issues that you have
> to "learn". Wow. The company would be much, much better off from every
> aspect to have the board designed by a seasoned professional PCB
> designer. Lower cost, certainly much better quality and a lot quicker.
> I'm sure you are an excellent engineer so please do not take offense. It
> takes years of experience to develop the expertise required to be a good
> PCB designer.
>
> Good luck.
>
> Best regards,
>
> Mario Irigoyen
> MPC Engineering
> [log in to unmask]
>
> [log in to unmask] Message-----
> From: DesignerCouncil [mailto:[log in to unmask]] On Behalf Of
> Joseph Matthews
> Sent: Monday, February 07, 2005 5:50 PM
> To: [log in to unmask]
> Subject: [DC] Designing PCB footprints
>
> Greetings,
>
> As a hardware engineer I have been tasked with laying out my first real
> circuitboard in years (first *real* board I guess). It's proved a bear.
> With years of experience designing hardware I am totally unprepared for
> the leap from the "logical" into the "physical" at this stage in my
> career. No less, I am under a crunch (as we all are, right?) and this
> being a fairly simple board, I figured it's time I dove in and
> learned...Simply stated, I'm stumped. Where can I find a comprehensive,
> clearly defined explaination on how to create *quality* PCB footprints
> and/or what the terms are used by the Footprint calculator made by PCB
> Libraries. I see all of these fields to enter information but I'm not
> sure what these mean and how to translate what's on the datasheet to
> these fields.
>
> I have read through a few of the IPC standards (some of the 122x stuff)
> and still can't say I undertsand much more of what's required. Is there
> a more comprehensive standard or something that more clearly deliniates,
> "do this...don't do this"...or, "if the pad is this big on the
> datasheet, add n%". These standards seem fairly high-level and at times
> seem almost circular. No less, they are not totally specific and I'm
> not sure where I can get the very specific information. I of course am
> aware that there's probably more to it than simply adding a bit here or
> a bit there, but assuming I know nothing, can someone offer some
> straight-forward advice on how to build up a board. Nothing fancy, just
> the basics. I should be smart enough to take it from there.
>
> I hate to inundate people with how-to's but everything I've read,
> including a book on the fundamentals of PCB layout seems very high-level
> and seem almost afraid to say anything for certain.
>
> Thanks for your help.
>
> Joe
>
>
>
> ---------------------------------
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