156.25 MHz fixed-frequency clock source
The LMK60E2-156M25SIAR is a fixed-frequency clock oscillator from Texas Instruments, delivering a 156.25 MHz output from a 3.3 V nominal supply rail. That frequency is a standard reference for 10GbE and 25GbE Ethernet PHYs, FPGA transceiver banks, and SerDes PLLs — the 156.25 MHz rate matches the line-rate divide ratio in most 10G/25G designs.
Supply and temperature tolerance
The oscillator expects a clean, regulated 3.3 V rail; a switching regulator with more than 50 mV ripple at the oscillator frequency can push the output jitter above the PHY's mask. It is not rated for extended automotive or downhole environments.
Housed in a 6-SMD Module (6-QFM) measuring 7 mm × 5 mm — a common oscillator footprint shared by many 7x5 mm SMD clock modules. The surface-mount package reflows with standard lead-free profiles.