Clock-tree design-in: what the 1.08 GHz PLL buys you
The LMK04111SQ/NOPB is a PLLatinum clock generator from Texas Instruments that integrates a phase-locked loop (PLL) to synthesize and clean up clock signals up to 1.08 GHz. That frequency ceiling covers the reference clocks for most high-speed ADCs, DACs, and SerDes transceivers — if your data converter needs a 1 GHz sampling clock, this part generates it from a lower-frequency reference without adding excessive jitter. The input stage accepts LVCMOS, LVDS, or LVPECL levels, so it interfaces directly with common crystal oscillators, VCXOs, or another PLL's output without external level translation. The output drivers deliver 2VPECL or LVPECL — differential signaling that rejects common-mode noise on the clock traces between the generator and the load. With a 2:5 input-to-output ratio, a single clock input fans out to five differential output pairs. That is enough to distribute a clean reference to multiple converters or logic devices on the same board without adding a separate fanout buffer.
Supply, temperature, and package — board-fit constraints
The device operates from a single 3.15 V to 3.45 V supply rail. That is a narrow window — the rail must be regulated to within ±5 % of 3.3 V; a 3.3 V LDO with 1 % accuracy is the safe choice. It comes in a 48-lead WFQFN with an exposed pad, supplier device package 48-WQFN (7x7 mm). The exposed paddle must be soldered to a PCB ground plane with adequate thermal vias — the datasheet's recommended footprint and stencil aperture are not optional; skipping them lifts the junction temperature above the rated limit under continuous 1 GHz operation.
It is suitable for both new designs and volume production. The base product number is LMK04111; the /NOPB suffix denotes lead-free (RoHS-compliant) finish.