Frequently Asked Question
If the port has a differential REF CLK, and I want to use a single-ended clock, what do I do with the other differential input?
In single-ended mode, we recommend tying the REF CLKB input to GND or VCC (it doesn't matter which). If the input floats, noise on that node could cause erratic clocking and induce additional noise on the clocking signal. It is never a good idea to leave a CMOS input floating.