Knowledge Base Article

Can we change the Rs and Rp resistor value of three-resistor network for LVDS_E_3R I/O standards?

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.

Updated 3 months ago
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