The DSC1121CM5-040.0000 is a MEMS-based XO (Standard) from Microchip's DSC1121 series, delivering a 40 MHz CMOS output with ±10 ppm frequency stability across a -55°C to 125°C military temperature range.
Microchip lists the DSC1121CM5-040.0000 as Obsolete. The 6-SMD no-lead package (3.20mm x 2.50mm, 0.90mm seated height) is a standard footprint for MEMS oscillators. A board spin would be required to migrate to a different oscillator family.
Operating from 2.25V to 3.6V, the oscillator covers 2.5V and 3.3V logic rails without a separate regulator. The 35 mA max supply current at 40 MHz sets the power budget for the clock tree; the 22 mA disable current is the standby draw when the output is gated off.