This is a Microchip Technology DSC6101MI2A-013.5600, a standard XO (oscillator) from the DSC61XX series.
Obsolete — sourcing through surplus channels
For a board that already uses this oscillator, the only practical path is to locate remaining stock through independent distribution. The 4-SMD, No Lead footprint (2.00mm x 1.60mm) is common in the DSC61XX family, but without a direct pin-compatible replacement from Microchip, a new design should migrate to an active part.
