400 Mbps full-duplex LVDS — the link budget decision
That 400 Mbps figure is the per-channel data rate, not an aggregate — it sets the serial link budget for point-to-point interfaces like camera serial links, display panels, or backplane data paths where signal integrity at 3.3 V matters. The 2/2 driver/receiver count means two independent transmit and two independent receive channels, enough for a bidirectional link with a spare pair for sideband signalling or redundancy.
If your design lives in a conditioned rack, a commercial-temperature LVDS part would save cost; for anything that goes outside or near a heat source, this grade is the right call.
Obsolete — sourcing reality for DS90LV049HMT
There is no pin-compatible direct replacement from TI with the same 2/2 driver/receiver count and 400 Mbps rating in the 16-TSSOP footprint; the closest functional alternative would be a newer-generation LVDS transceiver in a different package or with different channel count, which would require a board spin. If dual-sourcing is critical, qualify a second-source LVDS part in the same package early — the DS90LV049HMT is a single-source line that has already ended.