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3,788 Views
Registered: ‎01-17-2014

QSPI Supply VoltAge on KC705 Board

Hu,

does anyone know why the QSPI FLASH device on the KC705 is supplied by a  seperate 2.8V power supply ?

 

Regards,

Richard.

 

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Xilinx Employee
Xilinx Employee
3,780 Views
Registered: ‎01-03-2008

Because it is required by the QSPI device that is used.

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Community Manager
Community Manager
3,779 Views
Registered: ‎07-23-2012

The VCCIN range of QSPI flash on KC705 is 2.7-3.6 V.

Hence, that could be the reason for not choosing a 2.5 V or other supply source. But, I too don't know the reason why 3.3 V source was not used directly.
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Professor
Professor
3,772 Views
Registered: ‎08-14-2007

The SPI voltage needs to be compatible with Vcco of bank 0 and bank 14.  I'm not that familiar with the KC705 design, but on a board of my own I did exactly the same thing so I could use bank 14 at 2.5V for LVDS signals.  Thus my config voltage is 2.5 and ideally the SPI flash would also run at 2.5V, however most fast large SPI flash devices spec 2.7V minimum so I just run them at around 2.8V which is good enough to run fast and not high enough to turn on the clamp diodes on the 2.5V config banks of the K7.

-- Gabor
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3,758 Views
Registered: ‎01-17-2014

That explains it ....

Thanks Gabor.

 

Richard.

 

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