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Altera_Forum
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12 years ago

Cyclone V LVDS differential termination and RZQ

Hello, I am designing a board with differential LVDS interfaces (receive). I want to use the internal differential termination Rd and the manual is not very explicit on whether the RZQ resistor ha...
Altera_Forum's avatar
Altera_Forum
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12 years ago

You may want a clearer explanation in the manual, but it does distinguish between "OCT with calibration" and just "OCT" (without calibration). There's a table summarizing all available OCT variants, it says which of it have calibration.

Technically, OCT calibration is provided for those termination schemes that are using transistors as load, basically the same feature that provides programmable current strength. Differential Rd uses fixed termination, GX transceivers have calibrated differntial OCT.