2:10 fanout at 2.7 GHz — clock-tree fit
The MC100ES6111FAR2 is a 2:10 fanout buffer with an integrated multiplexer on the input side — one of two selectable clock sources fans to ten differential outputs. The 2.7 GHz maximum frequency covers the full range of 10G Ethernet reference clocks, FPGA transceiver reference oscillators, and SERDES PLL distribution. Differential input and output paths (Yes/Yes per the spec) reject common-mode noise coupled onto the clock traces between the source and the buffer, which is the dominant jitter mechanism on densely routed boards above 1 GHz.
Supply range and signal compatibility
Inputs accept ECL, HSTL, or PECL levels — a single device bridges between a PECL oscillator and an ECL-terminated fanout tree. Outputs are ECL or PECL, which require external termination resistors (typically Thevenin to VCC-2 V) rather than the series-source termination used for LVCMOS. The 32-LQFP (7x7 mm) package keeps the trace length from the output pin to the termination pair short enough to avoid stub reflections at 2.7 GHz.
Temperature grade and lifecycle
Note the RoHS compliance status: listed as RoHS non-compliant. This indicates a legacy lead-bearing solder finish (typically SnPb or AuSn). The part is still manufacturable and orderable, but the finish requires a Pb-compatible soldering profile — not a problem for mixed-technology assembly lines that maintain a SnPb reflow zone for legacy BOMs.