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taring77
Joined: 20 May 2004
Posts: 146
Helped: 2
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 28 Jul 2004 7:24 Highest BGA pin |
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Hi
i would like to know the highest no of BGA pins that anyone have succesfully routed and may i knoe what is the name of the i/c & what's it use for?
regards
taring
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Git
Joined: 12 Dec 2001
Posts: 1118
Helped: 1
Location: Torino
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28 Jul 2004 12:32 Re: Highest BGA pin |
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The largest Xilinx Virtex II FPGA chip is available in a 1704 pin BGA.
I wouln't like to route it, but anything is routable given enough layers.
Git
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majnoon
Joined: 11 Dec 2002
Posts: 271
Helped: 27
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28 Jul 2004 16:27 Re: Highest BGA pin |
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The highest bga I routed was 1152 FPGA Xilinx Spartan, with 1mm pitch.
I hand routed with 12 layers. One thing you should remember is that not all I/O's are always used also you can swap some I/O's for better routing.
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taring77
Joined: 20 May 2004
Posts: 146
Helped: 2
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29 Jul 2004 3:06 Re: Highest BGA pin |
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any possibility that you guys can share or can view the schematic / PCB layout??
i'm very interested.
What applications are these PCB for?
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29 Jul 2004 3:06 Ads |
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havi
Joined: 25 Jun 2004
Posts: 62
Helped: 2
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29 Jul 2004 10:36 Re: Highest BGA pin |
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Hai Git,
can you explain what are the minimum precautions to take for bga's.
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serg1976
Joined: 28 Jul 2004
Posts: 8
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29 Jul 2004 10:44 Re: Highest BGA pin |
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| majnoon wrote: |
The highest bga I routed was 1152 FPGA Xilinx Spartan, with 1mm pitch.
I hand routed with 12 layers. One thing you should remember is that not all I/O's are always used also you can swap some I/O's for better routing. |
Hi,
what PCB CAD have you used for routed 1152 FPGA Xilinx Spartan?
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Git
Joined: 12 Dec 2001
Posts: 1118
Helped: 1
Location: Torino
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29 Jul 2004 12:22 Re: Highest BGA pin |
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Havi - main thing is to totally plan the fanout from bga. Also see if the manufacturer has any recomendations or warnings. Some PCB programs are good at fanning out and some are not so good. It's likely that the bga will define the minimum number of layers of your board which will have signifcant affect on the cost, so an extra hour or two spent on the fanout may leave you with an 8 layer board rather than 12 layer.
Git
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pisoiu
Joined: 31 Dec 2002
Posts: 729
Helped: 24
Location: Romania
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29 Jul 2004 12:28 Re: Highest BGA pin |
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I just saw the price for Virtex family ( >$13.000 up to ~$19.000/1 pcs for xc2v8000 ), this one is also high pin count (>1000 user i/o). Mmmm...expensive.
/pisoiu
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majnoon
Joined: 11 Dec 2002
Posts: 271
Helped: 27
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29 Jul 2004 12:53 Re: Highest BGA pin |
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Hi,
what PCB CAD have you used for routed 1152 FPGA Xilinx Spartan? |
I used OrCad Layout 9.2.
As for fanning out BGA properly I agree with Git but if you have signals coming from inner pins of BGA there is not much you can do to reduce number of layers. Since for every signal you need one layer.
There is another technic that is to use Via in PAD and combine it with BB Vias this allows you to reduce number of layers significantly compare to traditional Dog Boning .
Hope this helps,
Majnoon
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