LVDS noise immunity

The current source in driver is always on and routed in different direction to drive logic ones and zeros.
This always-on characteristic eliminates the switching-noise spikes and EMI resulting from turning high-current transistors on and off. The two lines of the differential pair are adjacent to each other also providing noise immunity. Noise from crosstalk or EMI that is absorbed in one of the pair will also appear in the adjacent line. Since the receiver responds to the difference between the two channels, the common-mode noise that appears on both lines of the pair will cancel at the receiver. On the otehr hand, the two adjacent lines carry equal current but in opposite directions, EMI generation is minimized.

reference: LVDS Owner's Manual 4th edition 2008 from NS