BGA on 4-layers?

Hi,

I haven't directly done a layout with a BGA part yet. Is it possible to do a 400-pin or 500-pin+ BGA on 4-layers, or do I have to eat it and go to six?

As a follow-up, any reasonably cheap places in the US to do 4-layer and

6-layer prototypes? I've seen some that look good, but then follow up by saying "no step repeat" of the design...

Finally, if there aren't any good places in the US, what about overseas, such as Taiwan?

I'm trying to avoid China for concern of pollution -- I doubt that many PCB factories there are following strict environmental laws and *I* don't want make things worse.

Thanks H.

Reply to
H
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Ha! Amazingly, I was doing a little poking around on that EXACT topic last night. Funny timing...I didn't find a whole lot of info yet, so I will also be anxiously awaiting a few anecdotal responses (my guess is the per-project complexity will still have a ton to do with the answer...for my project, I want to drop a high ball-count FPGA onto a four-layer board, but I only need ~100 of the i/o lines actually being used for anything).

Await> Hi,

Reply to
john.orlando

Very difficult with 32 bits data paths. Nearly impossible with 64 bits data paths. Easier with off-board memory modules.

So, you feel better by having the Taiwanese to go to China for you? They rarely make the boards in Taiwan themself. Same for Singapore, Malaysia, etc. This is especially true for fine-pitch PCB, the equipments are too expensive without economy of scale.

Reply to
linnix

All I can say is start the layout and see if you can do it.

If you can fit it in 4 layers, try the no touch service at

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It worked nicely for a board I did with a 256 ball

1mm pitch part. About 220 balls were connected. I put some pictures of that board up at
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That one was particularly difficult due to the Spartan 3's 3 supply voltages.

Darrell Harmon

Reply to
dlharmon

to

overseas,

that

difficult

I'm just curious - did you succeed to solder BGA the first time or there were several attempts?

- Dejan

Reply to
Dejan

It worked the first time. I plan to try another batch of them soon.

Darrell Harmon

Reply to
dlharmon

Your at91rm9200 sbc seems interesting. However, the 16M memory is too small. Can you help us upgrading it to a 256M module? We can provide you with the prototyype boards and parts and cash. We want to hook it up to the module at

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Thanks

Reply to
linnix

Hi Linnix,

Does your company produce PCBs for prototyping? Would you offer you services to the general public?

You mentioned that most/all Taiwanese companies go through China.

What are the environmental laws in China with respect to things like PCB production? I know that in the US the chemicals may not (legally) be disposed of in a harmful manner.

Regards. H.

Reply to
H

Yes, we do prototypes, productions and assemblies. Right now, we have clients who need low end SBCs (Arm, PPC or X86) with lots of memory (256M+). We are trying to link them up with designers and manufacturers. we are still working out the system, but we can provide Java based PCB (gerber) previews to the manufacturers. It's good enough to ask for quotes without sending them the actual files. We only send the customer's gerber files to the selected manufacturer.

Right now, we have to send out the Java Applet (but not the data, which reside on our server), since it does not seem to work consistently with all browers. If you send me the gerber files, I will send you the applet to preview it. You can see if you feel comfortable with your design being send out that way, or with more protections.

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It's no worse than the Food and Textile industries, or many other industries there. Unless we stop buying foods and clothes anywhere (not just in China), we cannot stop the polutions. Of course, we can help by driving older and smaller cars (mine is a 1994 Toyota), since building a new car also cause lots of pollutions.

Reply to
linnix

Tough laws, on a par with many developed countries, but weak or spotty enforcement.

Dealing with ISO 14001 suppliers is probably your best way of handling this issue.

Best regards, Spehro Pefhany

--
"it's the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
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Reply to
Spehro Pefhany

I am not sure what you are referring to with the 16M memory. It has a

16Mbit (2Mx8) dataflash for boot, a 64-256MByte NAND flash and 32 to 64Mbytes of SDRAM. I have no interest in further persuing that board.

I am currently persuing production of DSPcard on my own.

Darrell Harmon

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Reply to
dlharmon

Yes, I realize that after studying the design further.

So, I hope you don't mind us taking over your design. We will keep your name as the original developer. We want to add 3 more SDRAM chips and IDE connector. We might change to the BGA version of both chips as well, since we would likely go to 6 layers.

I also send you a email separately.

Reply to
linnix

Since the original developer is no longer interested in this project, we are looking for volunteers to continue. We fixed the D2/D5 CF pin on the layout, but there are additional work to be done. The updated source packages (and additional information) are available at

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Anyone interested? Free prototype boards are available for developers!

Reply to
linnix

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