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vimalab
Explorer
Explorer
2,503 Views
Registered: ‎10-14-2014

About decoupling capacitor

good evening all

 

Am designing a new board which is used to configure an fpga using ftdi. Am started to draw schematics on it.

 

Can any one please tell me how to select decoupling capacitor value for my design? Based on which we should select decoupling capacitor value?

 

Thanks in advance

 

Regards

Vimala

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5 Replies
gszakacs
Professor
Professor
2,485 Views
Registered: ‎08-14-2007

Which FPGA family are you using?  Most families include a user guide for PCB design that details the recommended bypass network.

-- Gabor
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vimalab
Explorer
Explorer
2,473 Views
Registered: ‎10-14-2014

Good morning sir

 

Am using spartan 3AN fpga family.......

 

 

Thank you

 

Regards

Vimala

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gszakacs
Professor
Professor
2,462 Views
Registered: ‎08-14-2007

There is some mention of board design and power distribution in the Spartan 3 family User Guide which also refers to XAPP623.   While there is no table of recommended capacitors for this series, the principles are outlined in the app note.  You can also look for evaluation boards and kits with your part on them.  The schematics for these boards is generally available, and can give you a starting point for your design.

-- Gabor
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vimalab
Explorer
Explorer
2,449 Views
Registered: ‎10-14-2014

good morning

 

Thank ypu

 

 

Regards

Vimala

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umamahe
Xilinx Employee
Xilinx Employee
2,444 Views
Registered: ‎08-01-2012

To select decoupling capacitors you may refer example schematic in the following link http://www.xilinx.com/support/documentation/boards_and_kits/s3astarter_schematic.pdf

 

 

The theory part behind decoupling capacitor selection was given in http://www.xilinx.com/xapp/xapp623.pdf.

 

The below documents are also useful reference for your Spartan-3AN design

 

-The Spartan-3AN  board user guide http://www.xilinx.com/support/documentation/boards_and_kits/ug330.pdf .

-Methodologies for Efficient FPGA Integration into PCBs white paper http://www.xilinx.com/support/documentation/white_papers/wp174.pdf

 

 

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