What this LVDS fan-out buffer does on your board
The Texas Instruments SN65LVDS109DBTRG4 is a 1 x 2:8 LVDS buffer and multiplexer that takes one differential LVDS input and fans it out to eight LVDS outputs, with a second input selectable via the mux. It's designed for clock and data distribution in high-speed serial links where signal integrity matters — think backplane repeaters, base station clock trees, or test equipment needing to drive multiple receiver nodes from a single source. Each output channel handles data rates up to 400 Mbps with a propagation delay of just 2.8 ns, keeping skew tight across the fan-out. The 5 pF input capacitance and 46 mA supply current (typical) mean it loads the driving source lightly while staying power-efficient for a 1:8 buffer.
That means TI no longer manufactures it, and there is no direct factory path for new orders. If you have an existing design using this part, you are looking at last-time-buy inventory or the surplus channel to fill remaining production runs. That makes sourcing through independent distribution the practical route for bridging supply gaps.