Topic: FMC125 - VADJ voltage on VC7203 at 1.8 V  (Read 5675 times)

daniels December 11, 2013, 01:34 PM

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Hi,
We will connect four FMC125 cards to two VC7203 (carrier) boards.
  The VC7203 has a VADJ of 1.8V for all the FMC ports.
  The FMC12x manual (Oct. 2012) states: "The carrier card must support VADJ/VIO_B voltage of +2.5V (LVDS support) for
 FMC12X revision 1. The carrier card can support VADJ/VIO_B voltage range of

 1.65V to 3.3V for FMC12X revision 2, but typically VADJ will be 1.8V or 2.5V for

 LVDS operation."

  The 2 new FMC125 boards we just bought are revision 2. But the old ones are revision 1, therefore these two will not work in VC7203 according to the manual.
 
  a) I see that rev. 1 cards still have test points for 1.8V, so I assume they do include level shifters. If so, can I (or you) reconfigure the level shifters/card "easily" to get it working at 1.8V ? If not, please advice what you/we can do.
 
  b) For the rev.2 cards that are compatible with VC7203. Before inserting them on the carrier, do I need to change something in the card (dip-switch maybe?) to configure 1.8V operation?
Thanks,
Daniel
 
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arnaudNL December 11, 2013, 04:30 PM (#1)

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Dear Daniel,


a) There is an on board generated 1.8V for some circuitry and this is why a test point is on the board. I am afraid there is not much we can do understanding the card is simply not compatible. Maybe this is something you can discuss with sales, there might be solutions available on that front.


b) Revision 2.x have level shifters able to deal with various VADJ so no specific configuration is required.


Best Regards,
Arnaud