[Arm-netbook] SoC warp soldering risk?

Luke Kenneth Casson Leighton lkcl at lkcl.net
Sun Apr 23 06:20:47 BST 2017


---
crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68


On Sat, Apr 22, 2017 at 11:53 AM,  <sokolgeo at posteo.net> wrote:
> Hello. It seems like NEO900 project (http://neo900.org/) is having some
> problems with SoC warp soldering memory chips to their PCB:
>
> http://talk.maemo.org/showpost.php?p=1525427&postcount=2850
>
> https://irclog.whitequark.org/neo900/2017-03-14#19041338

 specific details:
 http://lists.goldelico.com/pipermail/community/2017-February/001583.html
 http://lists.goldelico.com/pipermail/community/2017-February/001594.html

> Luke - is there similar soldering risk in EOMA manufacturing?

 fuck no :)  whenever i see "PoP" as an option for a processor i run
away very very fast :)

 it's also why i haven't done a smart (or dumb) phone, because
*without* that smaller size (due to "stacking") you simply can't make
a small enough PCB for it to be socially acceptable, these days.

 that's why i was so excited when i found the Ingenic M150... and so
disappointed when they told me they'd stopped making it.  why?
because the M150 has 128mb of DDR2 RAM *on board* the same 11x11mm
package, as a Multi-Chip-Module.

 instead i've focussed on EOMA68 as the first modular design, which is
*just* big enough to fit processor and RAM and PMICs onto one side of
the PCB., and in some cases big enough to fit NAND or eMMC on as well.

 so no - the primary reason why i avoid PoP RAM is because of the MOQ
quantities usually being around 1,000.

 *sigh* another expensive learning experience for the open / libre
hardware community, there.  i do wish sometimes that they'd read some
of the things that i write.  i've *already learned* that you don't try
retro-fitting PCBs into pre-existing casework.

 never mind - sometimes it's better for people to do things they won't
listen on and then fail.

l.



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