PCIe clock distribution, no PLL involved
The Renesas 557G-06LF is a 1:4 fanout clock buffer designed specifically for PCI Express (PCIe) reference clock trees. It accepts either HCSL or LVDS differential inputs and delivers HCSL or LVDS outputs, with a fully differential signal path throughout — no PLL in the signal chain, so additive jitter stays low and the output phase tracks the input directly. The 2:4 input-to-output ratio lets you feed two reference clock sources (for redundancy or spread-spectrum switching) and distribute to up to four PCIe slots or endpoints.
200 MHz ceiling and what it means for your PCIe generation
Rated for a maximum frequency of 200 MHz, this buffer covers PCIe Gen1 (100 MHz) and Gen2 (100 MHz) reference clock requirements comfortably, with headroom for Gen3's 100 MHz or any 125/200 MHz non-standard clock trees. If you are planning Gen4 or Gen5 at 100 MHz, the 200 MHz ceiling still works — the buffer does not limit the data rate; the upstream clock source and the endpoint PHY set that. What matters is the additive jitter through the buffer, and the no-PLL architecture keeps it deterministic.
Supply and temperature — indoor gear only
Operates from a 3.3 V supply with ±5% tolerance (3.135 V to 3.465 V), which lines up with the standard PCIe auxiliary rail. The temperature range is commercial grade: 0°C to 70°C. That means this part is at home in servers, switches, desktop motherboards, and test equipment that lives in a climate-controlled room. Not rated for the engine bay or a rooftop enclosure in July — for that you would need the industrial-temperature sibling in the same family.
Package and footprint
Housed in a 20-pin TSSOP (4.40 mm body width), surface-mount only. The supplier device package is 20-TSSOP. Tube shipment is the standard format from Renesas; if your pick-and-place line prefers tape, the reel variant carries a different suffix. The 0.65 mm pin pitch is standard for TSSOP-20 — no surprises for the PCB layout.
Active lifecycle and sourcing posture
ROHS3 compliant (lead-free). This is a current-production part from Renesas, so no last-time-buy math or broker scavenger hunt needed.