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Altera_Forum
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19 years ago

My PCB design for Cyclone II ep2c20F484;ep2c35F484

I am begginer ir FPGA and the problem I have is with these development bords is that they are very expensive! cheapest bord I found with cyclone II ep2c20 FPGA is firefly bord with cost 350$ and its ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
19 years ago

maby You did't noticed but there is place for 23 (SMD 0805) decoupling caps for each power pin I think it could be enough or I can try to solder 2 caps on one place so I will totaly have 46 caps how about that ??

for 3,3V I curently have soldered one big 220uF cap.

I am thinking of 0,2uf caps is this value corect.

Here is osciloscope mesurement picture where I mesured 3,3v powersuply performance

blue line is probe from DC-DC regulator output and red line is probe from 220uF cap outut and load is one Led (20ma)+ 16Mhz oscilator and empty FPGA. soan i will solder EPCS16 configuration flash.

http://theonlyway.net/eoz/upload/attachmen...77&d=1169634985 (http://theonlyway.net/eoz/upload/attachment.php?attachmentid=2077&d=1169634985)

I think when I will solder these 23 0,2uf caps this voltage riple will be mutch smother http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/smile.gif