PCIe clock distribution in a 48-SSOP footprint
The 9DB803DFILF is a 1:8 differential fanout buffer with an integrated PLL, designed to distribute a clean 400 MHz reference clock across a PCI Express (PCIe) clock tree. The 48-SSOP package (7.50 mm body width) demands a standard surface-mount footprint — no fine-pitch rework required, though the 0.295-inch lead span means the board layout should match the SSOP land pattern, not a narrower SOIC. Input and output are both HCSL (High-Speed Current Steering Logic), the de facto signaling standard for PCIe reference clocks. The differential I/O path (Yes/Yes) means the buffer preserves signal integrity across the fanout — each of the eight outputs drives a separate HCSL-compliant load without the skew accumulation you'd see from a daisy-chain.
Supply headroom and temperature grade
If your board's 3.3 V rail droops below 3.135 V under load, the PLL may lose lock; budget the IR drop across the PCB trace and the regulator's load regulation into that floor. The industrial temperature grade (-40°C to 85°C) covers most outdoor and factory-floor deployments — an engine bay or direct-sunlight enclosure at 85°C ambient still leaves margin before the junction limit. At 400 MHz max frequency, this buffer supports PCIe Gen 1 through Gen 3 reference clock rates (100 MHz, 125 MHz, and the spread-spectrum variants). The 1:8 fanout ratio means a single input drives up to eight loads — useful for distributing the reference to multiple root complexes, switches, or endpoint PHYs without an external clock divider.