Resitor Terminsion for LVDS ARRIA V

For Arria V LVDS, there is indeed on chip termination resistor for RX. And if you are using ALTLVDS_RX and setup the input pin type as LVDS (of course), the 100 ohms termination resistor is on by default. In this case you don't need external termination resistor.

But in real world design, we will put the on-board termination resistors (at least for me). In this case, either you can de-solder the on board resistors or you need to turn the Arria V OCT resistor off manually.

here is the way to go in Quartus II assignment editor from the handbook, in order to turn it off, the value need to be set as "OFF".

https://www.alteraforum.com/forum/attachment.php?attachmentid=7395

It took me quite a while to figure this out since I noticed incorrect LVDS signal amplitude. In the handbook I found nothing about the default setting, on or off, for the LVDS OCT. Also the OCT type “Differential” together with other options such as "OCT 100" in pin assignment editor are confusing.

To you questions, LVDS standard only require 1 termination resistor in receiving end. There is nothing for the transmitting part. you cannot use DDR3 as the template because it use other differential standard.