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3.3V LVCMOS termination absent in Cyclone V??

Altera_Forum
Honored Contributor II
‎06-18-2013 12:19 PM
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Hello, 

I looked at table 5-29: selectable i/o standards for rs oct without calibration 

and table 5-30: selectable i/o standards for rs oct with calibration from cyclone v device handbook, and It seems there is no internal termination of any kind for 3.3V LVCMOS standard, while there is for 3.0V, 1.8V LVCMOS.  

Why? Is there sthg I did not get? I’m a bit surprised… 

 

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Altera_Forum
Honored Contributor II
‎06-20-2013 03:51 PM
354 Views

you are right. I guess 3.3V with on-chip termination will require more current so Altera decides not to support it. Most of the time 3.0V or 2.5V will be good enough for interfacing 3.3V signal with on chip clamp diode on. I would consider to use lower voltage if OCT is really needed.

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