I noticed on pg 15 of ver. 0.95 of the reference manual (Si5341-40-RM.pdf) that 200 ohm diff input impedance is suggested for XA/XB inputs. I believe this is an error.
This applies if we provide an external CLOCK input to the crystal pins.
If you connect a CRYSTAL to the crystal pins, then you should follow the recommendations in
5.1.1 (on the same page in reference manual) and section 12 beginning at page 47.
You are right. The 100 ohm resistors should each be 50 ohms.
Yes, I realise that. But for an ext diff i/p, impdedance is usually 100ohm.