Dual 156.25 MHz HCSL clock source
The DSC2044FE2-H0006T is a MEMS-based XO (Standard) from Microchip's DSC2044 series, delivering two identical 156.25 MHz outputs in HCSL logic levels — the frequency and signal type used as the reference clock for PCI Express Gen 1/2/3 and many 10GbE PHYs. HCSL (High-Speed Current Steering Logic) swings 700–800 mV peak-to-peak into a 50-Ω termination to ground, which means the same output can drive a PCIe slot or a SerDes reference directly without external level translation.
The 2.25V–3.6V supply range lets the oscillator run from a 2.5V or 3.3V rail without a dedicated regulator — useful when the board already carries one of those voltages for the FPGA or switch ASIC. Maximum supply current is 60 mA typical with both outputs active; disabling the outputs via the Enable/Disable pin drops the draw to 23 mA max, which helps meet standby power targets in line-card or access-point designs.
MEMS reliability and temperature range
Package and board layout note
The 14-VFQFN exposed-pad package (3.20 mm x 2.50 mm, 0.90 mm height) requires a thermal pad on the PCB for heat sinking — the pad also provides a low-inductance ground return for the HCSL outputs, which matters for signal integrity at 156.25 MHz.