Server clock tree fanout — one input, nine HCSL lanes
The 9FG108EGLF is a PLL-based clock generator from Renesas designed to produce up to nine HCSL outputs from a single clock or crystal input. It targets Intel CPU server platforms, PCI Express reference clocks, and SATA timing. The 1:9 fanout ratio means one clean reference source can drive multiple PCIe root ports or SATA controllers without adding separate buffers — a common topology on server motherboards where board space is tight and skew between lanes must stay low.
400 MHz ceiling and differential output discipline
Maximum output frequency is 400 MHz, which covers PCIe Gen1 through Gen4 reference clock requirements (100 MHz base with spread-spectrum) and SATA at 150/300/600 MHz rates. The differential output (HCSL) is standard for PCIe — single-ended inputs are accepted, so a crystal or LVCMOS clock source works without level translation. A clean 3.3 V rail with low ripple is expected; sharing this rail with a switching regulator without adequate decoupling can push the PLL jitter above the PCIe mask.
48-TSSOP footprint — reflow and placement notes
Housed in a 48-TFSOP (0.240", 6.10 mm width) package, also listed as 48-TSSOP. The 0.50 mm lead pitch is standard for this density — no exotic stencil or reflow profile required. Check the MSL rating before the first production run; a high MSL level means a bake step before reflow to avoid popcorning. Not rated for extended industrial or automotive temperature ranges.