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Spieler's avatar
Spieler
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7 years ago

Cyclone V LVDS deserializer bitrate

Hi, I am writing to see if we can identify the reason why the LVDS receiver of our system has problems to receive the incoming stream properly. The incoming stream comes from an LVDS ADC (AD9257) ...
Spieler's avatar
Spieler
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7 years ago

Hi Rs,

Thanks for your answer.

Yes, we are using the dedicated circuitry to deserialize the incoming stream. This is the reason why we do not understand what is going wrong. Timing is met, the differential termination is set as well, the length of the LVDS lines are matched, but still we have problems to receive the stream of data at 580Mbps.

My question regarding the termination was in the sense that for such a tolerance in the termination resistor (40%), it could (and it will) lead to reflections in the LVDS line that degrade the link. The question is how much it can be degraded because of this tolerance in the termination. From the datasheet it should be possible to receive data over 800Mbps, but maybe this is only possible when the termination is precise enough (external).

Has anybody succeeded to receive such rates using the internal termination?

Cheers