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[email protected] 11-22-2007 03:04 PM

Virtex 5 PCB Designers Guide: required capacitors
 
Hi all,

I've some trouble designing a virtex 5 board. I use the "Xilinx Virtex
5 LX development kit" schematic ( provided by Avnet ) as model, and
the Xilinx App Note "Virtex 5 PCB User guide 203".

My problem is about the capacitors required by the FPGA. In the pcb
user guide, there is a section wich details the list of required
capacitors / slices. Capacitors used are 330uF, 2.2uF, and 220nF.
But I was surprised when I look at the "Xilinx Virtex 5 LX development
kit" schematic, because only 100uF, 2.2uF, 100nF and a lot of 1nF are
used.. there is a lot of differences between the two..

So my question is, what do you think about that ? and what will you
advice to me ? Do you think it would be better if I add 1nF capacitors
for very high frequencies variations ?

Thanks by advance,

Best regards, Michel.

Symon 11-22-2007 10:39 PM

Re: Virtex 5 PCB Designers Guide: required capacitors
 
<[email protected]> wrote in message
news:[email protected]...
> Hi all,
>
>
> So my question is, what do you think about that ? and what will you
> advice to me ? Do you think it would be better if I add 1nF capacitors
> for very high frequencies variations ?
>
> Thanks by advance,
>
> Best regards, Michel.


Hi Michel,
Instead of starting yet another thread on bypass caps, perhaps you could go
and read the ones we've already had? There's plenty to choose from. Google
groups or fpga-faq.com for comp.arch.fpga .
If you want the latest and greatest technology, do a google search for X2Y
caps.
Cheers, Syms.




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