Multi-output HCSL clock source for dense timing trees
The DSC400-4444Q0015KE2 is a MEMS-based XO (Standard) that delivers four HCSL outputs from a single 20-VFQFN package — two banks at 25/50/125/150 MHz and a second pair at 100/156.25 MHz. That covers a typical networking reference set (PCIe Gen3 100 MHz, 1GbE 125 MHz, SATA 150 MHz) without separate oscillators for each rail. The ±25 ppm frequency stability holds across the full -20°C to +70°C commercial range and the 2.25V–3.6V supply window, so a 2.5V or 3.3V rail feeds it directly without an LDO.
MEMS oscillators start up in under 5 ms typical (vs 10–20 ms for a quartz XO) and survive 50,000 g shock — useful if the board sees handling in assembly or vibration in a fan-cooled chassis.
The 20-VFQFN with exposed pad (5.00 mm × 3.20 mm, 0.90 mm height) needs a thermal via array under the paddle for the pad solder joint reliability — the datasheet landing pattern is the reference, not a generic QFN footprint.
If a second-source is needed, the closest functional match would be another MEMS XO with the same output format and frequency plan — but the pinout and supply range must be verified against the target socket.