Dual-frequency MEMS clock source for PCIe and Ethernet
The DSC400-4444Q0023KE2 is a MEMS-based XO that outputs two fixed frequencies: 100 MHz on output 1 and 156.25 MHz on output 2, both in HCSL logic level — a differential standard common to PCIe reference clocks and 10GbE SerDes. The base resonator is MEMS rather than quartz, which gives better shock and vibration tolerance — useful if the board lives in a portable instrument or a fan-cooled chassis where quartz can micro-fracture over time. Supply voltage spans 2.25 V to 3.6 V, so it runs off a 2.5 V or 3.3 V rail without an extra LDO.
Rated for -20°C to 70°C, so it belongs in an indoor PCB or office equipment, not an engine bay or outdoor telecom cabinet. Frequency stability is ±25 ppm across the full temperature range — tight enough for most 1GbE and PCIe Gen 3 links without needing a TCXO.
Microchip lists the DSC400-4444Q0023KE2 as Active — no last-time-buy window or NRND flag, so it can go into a new design without worrying about a sudden EOL notice. Sourced through independent distribution; quoted to order against the BOM quantity.