New Life in Openmoko Phones

Werner Almesberger werner at
Tue May 19 19:32:26 CEST 2009

Nils Faerber wrote:
> This would be one of the details I am interested in, i.e. would OpenMoko
> Inc. help in making (read as "producing") this new design? With its part
> stock, manufacturing capabilities, etc.?

Access to components is currently under discussion, yes. There are
at least some logistical issues, i.e., the GTA02 components seem to
be at a place where it's difficult to move them. But we're working
on it ...

The idea is indeed that we can get most of the components from
Openmoko. It's not only about the cost of the material but also the
difficulty of sourcing certain parts and the errors that could be
introduced in the process.

> Many of the parts in the GTA02 cannot be reasonably placed by hand.
> There are almost a dozen (or more?) BGA chips which are extremely hard
> to handle (you do not see if the balls match the pads).

Hehe, this reminds me of the usual "SMT sucks, where can I get this
chip in DIP ?" discussion. This question is usually followed by
someone suggesting some more or less crazy scheme that actually does
yield a DIP component, and a number of people explaining their
techniques for soldering SOIC and even SSOP. Then usually someone
chimes in describing how to solder QFN and the like with often
grossly inadequate equipment. And often enough, this ends with hints
for how BGAs can be done with kitchen utensils :)

I'm not sure where exactly the line between "unusual skills and
know-how" and "(not very hard) science fiction" lies. There's scary
stuff out there, though, e.g.,

Anyway, back to reality. I agree that this needs a real SMT production
line. There are some parts that can be difficult to SMT (buttons,
connectors) that are better hand-soldered, but for most of the items,
you want a properly quality-controlled and automated process.

Please bear in mind that the objective of gta02-core is not to make a
design that's immediately ready for mass-production but to set up the
process and make a small number of prototypes.

If some company should find the result appealing enough to turn this
into a real product and make the corresponding inventments, that would
of course be very welcome. But we can't count on this happening so

If you have contacts with companies that make prototype SMT runs, it
would be interesting if you could get rough cost estimates from them.
Let's assume the following parameters:

- 150-200 different components, all of them in reasonably common
  packages, on tape.
- most difficult component is a 332-FBGA with 0.5 mm pitch (the
  S3C2442B MCP)
- 500-600 components in total.
- 10-20 units produced.

> Then there are
> almost microscopic parts like resistors and capacitors - which pitch?
> 0402 at least if not even 0201 or smaller.

0402 is the smallest. For manual soldering (e.g., rework), size is
less of a problem than density.

- Werner

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