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From: John Adair on 13 Mar 2006 13:25
We are doing our best to patch that hobbiest hole. We we get some more time
there will be some more products coming for that market.

John Adair
Enterpoint Ltd. - Home of Raggedstone1. The low Cost Spartan-3 Development
Board.
http://www.enterpoint.co.uk


"Benjamin Todd" <benjamin.toddREMOVEALLCAPITALS(a)cernREMOVEALLCAPITALS.ch>
wrote in message news:dv49cf$s2f$1(a)sunnews.cern.ch...
> Hi Paul,
>
> You might manage the flat pack stuff with a tiny soldering iron and a bit
> of luck, but the bgas are a different story. Even the 'professionals'
> mess up when soldering these.
> - aligning the BGA almost perfectly to the grid on the PCB is tricky
> - Soldering these needs an oven with a compatible heat-curve, which
> changes from lead-free to leaded components.
>
> Just last week I had two s2 200s that had to go to be x-rayed, turned out
> they weren't soldered at the right temperature...
>
> So I wonder what your motivation is for this? If you're starting out, try
> and get your hands on some starter kits, they're really good value, and
> you can learn loads from them.
>
> If you're a student then go nag the electronics department, they should be
> pleased you're taking an interest, and might have some stuff lying around,
> plus if you could get some university-modules under your belt it would
> look nice on your CV.
>
> Mind you, there's so much to be said for just doing things as you become
> interested.
>
> I have to be honest and say that one of the big things that these Xilinx
> and Altera chaps are missing out on is the hobbyist engineer-type. If
> only they had that in mind when they built some of these starter kits,
> they'd sell them by the shed-load.
>
> Ok, just my 2p.
> Ben
>
> "Paul van der Linden" <msn(a)paultjuh.org> wrote in message
> news:44159b38$0$2337$2e0edba0(a)news.tweakdsl.nl...
>> Hi,
>> I'm very new to fpga, just came interrested in these things.
>> The only problem I think I will have is the soldering.
>> How to solder fpga's on the boards? I'm a student so I don't have money
>> for very expensive machines.
>> I want to be able to solder the whole range of packages of Xilinx
>> spartan 3e, will that be possible with not to expensive tools?
>>
>> Package types:
>> Table 121: Xilinx Package Mechanical Drawings
>> Package Web Link (URL)
>> VQ100 / VQG100: http://www.xilinx.com/bvdocs/packages/vq100.pdf
>> CP132 / CPG132: http://www.xilinx.com/bvdocs/packages/cp132.pdf
>> TQ144 / TQG144: http://www.xilinx.com/bvdocs/packages/tq144.pdf
>> PQ208 / PQG208: http://www.xilinx.com/bvdocs/packages/pq208.pdf
>> FT256 / FTG256: http://www.xilinx.com/bvdocs/packages/ft256.pdf
>> FG320 / FGG320: http://www.xilinx.com/bvdocs/packages/fg320.pdf
>> FG400 / FGG400: http://www.xilinx.com/bvdocs/packages/fg400.pdf
>> FG484 / FGG484: http://www.xilinx.com/bvdocs/packages/fg484.pdf
>
>


From: Uwe Bonnes on 13 Mar 2006 13:41
Paul van der Linden <msn(a)paultjuh.org> wrote:
> Hi,
> I'm very new to fpga, just came interrested in these things.
> The only problem I think I will have is the soldering.
> How to solder fpga's on the boards? I'm a student so I don't have money
> for very expensive machines.
> I want to be able to solder the whole range of packages of Xilinx
> spartan 3e, will that be possible with not to expensive tools?

> Package types:
> Table 121: Xilinx Package Mechanical Drawings
> Package Web Link (URL)
> VQ100 / VQG100: http://www.xilinx.com/bvdocs/packages/vq100.pdf
> CP132 / CPG132: http://www.xilinx.com/bvdocs/packages/cp132.pdf
> TQ144 / TQG144: http://www.xilinx.com/bvdocs/packages/tq144.pdf
> PQ208 / PQG208: http://www.xilinx.com/bvdocs/packages/pq208.pdf
> FT256 / FTG256: http://www.xilinx.com/bvdocs/packages/ft256.pdf
> FG320 / FGG320: http://www.xilinx.com/bvdocs/packages/fg320.pdf
> FG400 / FGG400: http://www.xilinx.com/bvdocs/packages/fg400.pdf
> FG484 / FGG484: http://www.xilinx.com/bvdocs/packages/fg484.pdf

All VQ/PQ/TQ packages can be soldered by hand with decent
equipment. Serveral Websites give sort of tutorials. You can also inspect
all contacts easily.

All CP/FG package require much more expensive printed circuits boards, can
only be solder with much more expensive equipment and are hard to inspect
after solder. Nothing for the beginner.

But for the start, buy some development board, so you don't need to solder
the FPGA at all.

Bye
--
Uwe Bonnes bon(a)elektron.ikp.physik.tu-darmstadt.de

Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt
--------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------
From: Andre Schäfer on 13 Mar 2006 13:43
Hi,
for self-soldering BGAs have a look at
http://www.lrr.in.tum.de/~acher/bga/
German only, but maybe helpful anyway. Nothing seems to be impossible ;)

Andre

Benjamin Todd wrote:
> Hi Paul,
>
> You might manage the flat pack stuff with a tiny soldering iron and a bit of
> luck, but the bgas are a different story. Even the 'professionals' mess up
> when soldering these.
> - aligning the BGA almost perfectly to the grid on the PCB is tricky
> - Soldering these needs an oven with a compatible heat-curve, which changes
> from lead-free to leaded components.
>
> Just last week I had two s2 200s that had to go to be x-rayed, turned out
> they weren't soldered at the right temperature...
>
> So I wonder what your motivation is for this? If you're starting out, try
> and get your hands on some starter kits, they're really good value, and you
> can learn loads from them.
>
> If you're a student then go nag the electronics department, they should be
> pleased you're taking an interest, and might have some stuff lying around,
> plus if you could get some university-modules under your belt it would look
> nice on your CV.
>
> Mind you, there's so much to be said for just doing things as you become
> interested.
>
> I have to be honest and say that one of the big things that these Xilinx and
> Altera chaps are missing out on is the hobbyist engineer-type. If only they
> had that in mind when they built some of these starter kits, they'd sell
> them by the shed-load.
>
> Ok, just my 2p.
> Ben
From: aiiadict on 13 Mar 2006 13:46
how about a BGA to DIP converter socket?

or, a BGA part pre-soldered to a board with
through-holes for attaching connectors, wires,
etc?

spartan3 + power supply + SRAM on a stamp-sized
board with breadboard type connectors on it? I know
breadboard spartan3 dev boards are available, but
it would be cool to get something tiny, cheap, and easily
connected to. minus the switches, LEDs, 7segment
LEDs, etc.

From: fpga_toys on 13 Mar 2006 14:04

Paul van der Linden wrote:
> Hi,
> I'm very new to fpga, just came interrested in these things.
> The only problem I think I will have is the soldering.
> How to solder fpga's on the boards? I'm a student so I don't have money
> for very expensive machines.
> I want to be able to solder the whole range of packages of Xilinx
> spartan 3e, will that be possible with not to expensive tools?

Contrary to others experience, I've done BGA parts pretty successfully
in "hobby mode", as well as with professional rework equipment. I've
developed a few "tricks" that help.

First, solder paste is very difficult to manage with hand placement.
Instead, use water soluable flux on the board pads, and push a large
solder ball over all the boards pads till you have a small shinny
solder mound on each pad with a fairly uniform size to attach the BGA
with. Clean the board well to remove the used flux, and apply fresh
flux to both the board and the BGA balls.

Second, position the BGA part on top of the pcb pads. It's very useful
at this point to have a silk screened outline of the package to center
the part with, that is very close to the real package size.

Third, carefully place in a preheated convection oven, and bake. The
correct time for this takes some practice and calibration of YOUR
setup. Visually verify that the balls have a uniform "squat" on all
four sides ... this generally means the parts wetted fine, and the part
settled down on the balls at reflow temp.

Read the lit about recommended profiles for various packages ... you
may not be able to exactly do those profiles, but you can come close
with some practice.

I've had pretty good luck using several different table top forced air
"convection ovens" with digital controls. These are fairly inexpensive,
and typically can regulate temps within 10 degrees F or so. Their
problem, is uneven air flow which may result in uneven board heating if
you do not give this some thought. Two of the ovens I used, required
setting the board on a soda can near the center of the oven, with the
turn table removed. A third oven required fashioning a foil air duct to
make sure the hot air flow evenly covered the board.

I suggest getting a non-contact IR thermometer with a spot capability
.... these can be had fairly cheaply from a number of discount sources,
including Harbor frieght. Using a salvage pcb of similar size and mass
as your "test board" you can experiment with your "profile". I would
suggest starting with the oven preheated to about 10-25F higher than
your expected solder temp, quickly inserting your test board, and
letting it bake for 2-3 minutes, open the door and quickly read several
spots on the test board with the IR thermometer before the cool air
drops the temp too much. Let the test board cool back to room temp, and
repeat several times increasing the bake time about a minute each time.
When you find the point where the board just reaches the solder temp,
you can then program the oven to turn off 2 min after reaching that
temp, and slowly cool the board back down without thermal shocking the
BGA.

Another process, is to pickup some slavage BGA parts with a similar
package, and make a test board with the on die thermal diode brought
out to test points, so you can run the wires out the door and monitor
the die temp as you develop your thermal profile. You can also do this
with your own board and FPGA's. You can also epoxy attach several
thermal diodes to a test board, and monitor the profile in real time at
several points.

Pickup some Solderquik reballing preforms for the parts you plan to
use. That way you can clean off your mistakes, and reball the parts to
try again.

The one thing you do not want to do, is get the newer BGA's too hot, or
thermal shock them with cold air. Older parts in BG432 and BG560
packages are much more forgiving. I would suggest learning this
process with XC4K, Virtex, or Virtex-E parts in BG432/BG560 packages,
and once mastered move on to newer high density packages.

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