Please allow me to get into this Q&A session.
As Matsumoto-san stated, I will use CDCM6208 in pin #14 mode with
a crystal resonator connected to SEC_REFP/N.
So, no signal is applied to PRI_REFP/N pins.
You recommend that unused PRI_REFP/N pins are either left open
or ideally connected to VCC or GND.
Q1. I concern that the differential inputs like LVDS is noise sensitive when
the differential input pair are left open.
The CDCM6208 is well design to avoid such noise?
Q2. If the differential input P and N is connected to VCC and
GND respectively, does such circumstance violate the LVDS input
Specifications. (Differential input voltage swing, peak-to-peak,
must be bellow than 1.6V)
Q3. If both the differential input P and N is connected to VCC or GND,
does such circumstance make differential input be in quiet mode?