[Coco] A question for all you hardware hackers out there...

[tim at franklinlabs.com]

I actually haven't chosen the actual FPGA yet because I'm not sure how much LE
space I need. I was considering a small Cyclone III or equivalent. The one I was
looking at I thought was 264 pins but it actually was 408. Anyway, I was just
trying to get a feel for what others have done. I have soldered small pitch SMT
components before but the FPGA's are pricy and mistakes can hit the pocketbook
pretty hard.

I'm still in the "investigating" mode of the project.


> On October 30, 2014 at 12:21 PM Camillus Blockx <camillus.b.58 at gmail.com>
> wrote:
>
>
> Hi, Tim
>
> A quick look on the web with google told me that there are no sockets around
> for that kind of carrier. So in case there are no substitudes for the chip you
> are using, in a different case, then the only option is to do the soldering
> yourself or give it out to the proffesionels. Now QFP devices are a bit easier
> to solder then the BGA. This because te leads are visible with the QFP. The
> BGA is more like guessing because the dots ( ballgrid) is not visible.
>
> Being that said, it is not so diffcult to solder QFP, a focused heat source,
> from blowheater, or even a high wattage infrared or halogen bulb will sufice.
> I myself used a blower, but having a project to use 75 watt 12 volt spots.
> Then you also need solder paste, or a good solder with resin. It would also be
> a good idea to soldermask your pcb, so the solder would easily and fast bind
> to the litle surface islands. If that is all done it is just a matter of place
> the chip on top the presoldered islands, line it up verry securely, lay a
> piece of heavy metal ( copper or iron) on top of the chip, check allignment
> and heat the leads evenly ( circle around the chip). With the 75 watt spot it
> is just a matter of waiting until the heat reaches the meltingpoint of the
> solder.
>
> If you can tell me the part number of the FPGA you use then I can buy one and
> do a test.
>
> Hope this helps you.
>
> camillus
> On 10/30/2014 10:39:32 AM, tim at franklinlabs.com <tim at franklinlabs.com> wrote:
> I'm looking at continuing the development of a CoCo hardware project I started
> a
> few years or so ago. The project is FPGA based and will use a medium density
> QFP
> chip (284 pins). My question is; how do hobbyists manufacture low quantity
> PCB's
> that have such a part or even BGA components? Soldering devices are just not
> practical and there doesn't seem to be a viable remote carrier that I can find
> that will allow the part to be installed on a PCB without it being installed
> by
> a professional board house.
>
> There's gotta be a better way. PLCC's were a good alternative but the
> densities
> on current FPGA's are beyond the PLCC relm.
>
> Any ideas or suggestions????
>
>
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