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  #1  
Old 04-19-2008, 09:58 AM
Grant Stockly Grant Stockly is offline
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Default Test Board

I don't know if this chip is a good idea. Its just too small. The trace and space is TINY. I think since it will require a CPLD, it would be better to write a refresh block and use cheap LARGE DRAMs.



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  #2  
Old 04-19-2008, 10:12 AM
Reactive Reactive is offline
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Hey Grant.

You use WinQ CAD? What size traces did you use? 8 mil is about as small as we can go without getting a price penalty.

After actually seeing that pic we may be forced to go 4 or even 5 layer, without Ground or Power plain.


Henry
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  #3  
Old 04-19-2008, 01:20 PM
rgjones rgjones is offline
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Default Trace width costs

Given the .75mm ball spacing

Gold Phoenix for example charges

155 Sq inch
2 layer base cost $99
6mil/5mil/4mil trace width/ clearance(2layers) $20/$40/$60

4 layer base cost $330
6mil/5mil/4mil trace width/ clearance(4layers) $40/$80/$200

If our breakout board was 4 sq inches for example that would yield about 38 peices so below is the cost per piece for reference

Trace widths
8 6 5 4
2 layer 2.55 3.07 3.58 4.10
4 layer 8.51 9.54 10.58 13.67


Since I have ordered with them before I might be ablet to get another 10% off

Last edited by rgjones; 04-19-2008 at 02:03 PM.
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  #4  
Old 04-19-2008, 01:46 PM
Reactive Reactive is offline
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Yikes! Now I see why those VFBGA Adapters quoted from Aries are so much.

Grant: What are the clearances on your design? I also assume that pic is two layers? Give me some GERBER files and I can get some price quotes. Can you also post a pic of a blow up on the PSRAM area so I can get an idea as to the trace spacing and layout?

Glenn: I've been using QualityPCB.com. They have had the best prices for 2 layer stuff that James and I have found.

Last edited by Reactive; 04-19-2008 at 01:51 PM.
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  #5  
Old 04-19-2008, 02:17 PM
rgjones rgjones is offline
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Quote:
Originally Posted by Reactive View Post
Glenn: I've been using QualityPCB.com. They have had the best prices for 2 layer stuff that James and I have found.
I just ran through the quote system for a panel the same size as GP and it came out to $130 and then they will add shipping to that. and it seems I have to panelize the board myself.

GP is $99, they panelize the board if it is repeat of same pcb and it includes shipping

You might want to give them a try - http://www.goldphoenixpcb.biz/special_price.php

Tell Shane that Glenn from a2retrosystems sent you .... )
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  #6  
Old 04-19-2008, 02:24 PM
Reactive Reactive is offline
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Hey Glenn.

Thanks for the info. I do have one design I need quoted right now. I'll email him and see what prices he gives me.

I know I asked them for a quote just about a month ago and they were a bit higher. Think James had the same experience too. Maybe it's just the little panel stuff they have the best price with. Hard to say as it seems some guys specialize in one thing, yet others give better prices on something else.

I'll post the prices here and let you know who I went with.
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  #7  
Old 04-20-2008, 06:58 AM
Grant Stockly Grant Stockly is offline
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When I was testing one of my boards I found out DigiKey sent me the wrong parts. So I had to use a DIP version. Check out what I had to do.

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  #8  
Old 04-20-2008, 01:39 PM
Reactive Reactive is offline
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Oh geeze! Yeah, that's exactly what I'm hoping to avoid. All in all, that's not too bad though. Don't you just love Bell Wire? ;-) I use it all the time too.

Anyway, you're call I guess. If you guys feel that it's a simple enough project where starting with a PCB is a good idea then I'm with you. I've just been there were I need to change the wiring and have to cut and wire traces. With 12 mil tracks it's not too bad, just a pain. 8s get a little hairy though.
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  #9  
Old 04-20-2008, 08:52 PM
rgjones rgjones is offline
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http://www.solder.net/services/estimate.asp

using their estimator - they charge $11.25 per mounted BGA device whch is the best I have seen so far - just surfing the web.
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  #10  
Old 04-20-2008, 09:01 PM
rgjones rgjones is offline
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Interesting Powerpoint presentation on BGA's

http://www.pcblibraries.com/download...ions%20PPT.pdf

also

http://www.adcom.co.il/pcb%20layout/..._Placement.pdf

Last edited by rgjones; 04-20-2008 at 09:12 PM.
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