PCIe clock distribution — what this buffer does on the board
The Renesas 9DBU0841AKLF is a 1:8 PCI Express clock buffer with an integrated PLL, fanning out a single HCSL reference clock to eight LP-HCSL outputs. It runs on a 1.425V to 1.575V supply rail.
1:8 fanout — enough for a multi-slot backplane
One input drives eight output copies. That's enough to clock a half-dozen PCIe slots plus the chipset on a standard ATX server board, or to distribute the refclk across a compact PCIe switch fabric. The differential input and output (Yes/Yes) keep signal integrity intact across the fanout tree — no single-ended conversion losses to budget for.
Temperature grade — indoor equipment only
Rated 0°C to 70°C, so this part belongs in a temperature-controlled server room, telecom central office, or office equipment — not in an outdoor base station or under-hood automotive ECU. If your BOM calls for a wider range, the 9ZXL0851EKKLF covers -40°C to 85°C but runs on a 3.135 V supply and uses standard HCSL outputs, not LP-HCSL.
Package and footprint — 48-VFQFPN, 6x6 mm
The 6x6 mm exposed pad needs a thermal via pattern under the pad for the supply rail's return current. The exposed pad is the ground connection — don't leave it floating. Surface-mount only; no through-hole equivalent exists.
Sourcing and lifecycle — active, no LTB risk
The 9DBU0841AKLF is listed as Active and ROHS3 compliant. For dual-sourcing, the closest functional peer is the 9DB803DFLFT — same 1:8 fanout, same PCIe purpose, but its output is standard HCSL (not LP-HCSL) and it runs on a 3.135 V supply, so the rail and output swing differ. A direct drop-in it is not; verify the downstream receiver's input threshold before swapping.