3.1 GHz fanout buffer with universal input mux
The Texas Instruments LMK00308SQX/NOPB is a fanout buffer, multiplexer, and translator designed for high-speed clock distribution. It accepts a wide range of differential and single-ended input standards — CML, HCSL, HSTL, LVDS, LVPECL, SSTL, and crystal — and outputs HCSL, LVCMOS, LVDS, or LVPECL. The 3:1 input multiplexer feeds a 1:9 fanout buffer, delivering up to 3.1 GHz on the differential outputs.
The part operates from a 3.15 V to 3.45 V supply — a tight 3.3 V rail with 5 % tolerance.
Housed in a 40-WFQFN with an exposed thermal pad (6 mm × 6 mm body). Reworking this package needs a preheat profile that brings the board to 150°C before the hot-air nozzle touches the part; the exposed pad is the last joint to wet, so a bottom-side preheater helps avoid cold solder on the ground slug.