Dual LVPECL outputs for networking clock trees
The DSC400-0202Q0106KE2 is a dual-output MEMS-based XO delivering 153.6 MHz on output 1 and 155.46875 MHz on output 2, both LVPECL logic levels — a common pairing for 1GbE and SONET/SDH line cards where the MAC and PHY require separate reference clocks at slightly different rates. Frequency stability is ±25 ppm over the -20°C to +70°C commercial temperature range, which keeps the bit-error rate within spec for most 1.25 Gbaud serial links without needing a TCXO.
The supply range spans 2.25 V to 3.6 V, so it runs directly off a 2.5 V or 3.3 V rail without an intermediate regulator — one less BOM line for the power tree.
MEMS resonator advantage over quartz
MEMS oscillators typically have shorter factory lead times than quartz-based XOs because the resonator is fabricated in a standard CMOS-like process rather than requiring quartz blank cutting and tuning.
The 20-VFQFN exposed-pad package (5.00 mm x 3.20 mm, 0.90 mm height) requires a thermal pad on the PCB for both heat sinking and mechanical stability — the exposed paddle should be connected to the ground plane with multiple vias to keep the junction temperature within the -20°C to +70°C operating range.