Description
In Altera® device handbooks, there is a three-resistor network requirement when using the LVDS_E_3R I/O standard, typical values for Rs is 120 Ohms and for Rp is 170 Ohms.
The parallel resistor values of Rs and Rp/2 should meet 50Ohm requirements assuming a 50 Ohm trace impedance. You can change the Rs and Rp values of the three-resistor network to meet your board requirements.
You should confirm your resistor values meet your signal integrity needs by running an IBIS simulation.