125 MHz fixed-frequency XO for SERDES and converter clocks
The LMK61E2-125M00SIAR is a 125 MHz fixed-frequency clock oscillator from Texas Instruments, packaged in a 6-SMD 6-QFM (7x5 mm) module. It draws 162 mA from a 3.135 V to 3.465 V supply rail, making it a drop-in reference for 3.3 V clock trees in high-speed data systems.
Supply margin and power budget
The 3.135 V to 3.465 V supply range is a tight 5% window around 3.3 V. The upstream regulator must hold its output within this band across load and temperature — a 3.3 V rail that droops to 3.1 V under full load will pull the oscillator out of spec. At 162 mA typical supply current, a single oscillator adds roughly 0.5 W to the board thermal budget. In a dense clock fan-out design with multiple devices, this current sums quickly and may drive a local LDO or a wider copper pour for heat spreading.