having been in such a situation before i would suggest just making your
own based on the mech dwg with pad dimensions adjusted according to your
there are not a lot of pins on those uMax

the slight (but important) differences in footprints are as much a
matter of the particular assy process as anything else

there are various rules of thumb as to the heel and toe extensions
pad width is yet another matter
the rules of thumb tend to break down as the dimensions get smaller

I understand why the chip vendors don't show actual footprints on the
finer pitch stuff
they don't want the grief/lawyer if there are problems, give the
customer the pkg dims and then it is their problem according to their
process window
there really isn't any one entirely perfect footprint for these things

at the finer pitches the type of paste and the quality of the stencil
wall hole and other specs of the stencil all interact with the design of
the footprint

I would take my best shot, make a small number and inspect and review
closely with your assembler
odds are that even if you had the IPC footprint you would not be home

I have seen people make WORKING boards with the pad width so great as to
disallow solder mask between, I also have seen and read testimonials
from people who insist that the pad should actually be narrower than the
device lead to avoid bridging

then there is the 'pad defined' (I think it is called) where the solder
mask expansion is actually negative and by design is on the pad so as to
create a dam for the paste which would seem to fly in the face of past
experience where any SM impinging on the pad inhibited solderablity

what if you had the 'standard' and it didn't work for you?
adjust your process to fit the standard?
or adjust the footprint to fit your process?
these issues get down to fundamental issues of freedom and choice
(including of course the freedom to hang yourself)

as to the '$ free' I wouldn't presume to know the answer
this is like the populist issue: 'a chicken in every pot'
free airfare would be nice, but would it enhance safety?
it actually might, or maybe it might not, but someone or some entity has
to pay

as somebody once quipped "the best number of standards is either one or

sorry to have rambled and good luck with your footprint

Dennis Saputelli

Bagotronix Tech Support wrote:
> Hello, all:
> Does anyone have a land pattern (footprint) for the uMAX10 package?  If so,
> I would appreciate a copy of it.  Please send it to my e-mail address, not
> the Protel group.
> This is used by a Maxim part, and I called Maxim for the recommended land
> pattern.  They didn't have one, and told me to look on my "program disk" for
> the JEDEC type M0187.  I finally figured out that what they meant was "call
> IPC and get the land pattern".
> Well, I went to IPC's website, and didn't find anything useful.  It looks
> like you have to pay for anything useful.  I guess it's one of those "open"
> standards that is really only open if you pay the standards body $$$ to get
> a copy of it.  Phooey on that!  I just want a downloadable electronic
> version, I don't need another piece of paper.
> I am tired of standards bodies locking up all the vital information with
> copyrights and big fees.  IEEE is probably the worst in this regard.  In the
> Internet age, open standards should be distributed electronically for free.
> They can charge for paper copies and physical media.
> Thank you in advance for your help.
> Best regards,
> Ivan Baggett
> Bagotronix Inc.
> website:  www.bagotronix.com

www.integratedcontrolsinc.com            Integrated Controls, Inc.    
   tel: 415-647-0480                        2851 21st Street          
      fax: 415-647-3003                        San Francisco, CA 94110

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