What kind of circuit drives the crystal in AD9953?
For a typical circuit for the Ad9953 , see the circuit of the AD9954 attached.
Exactly the same circuit can be used for the AD9953. A BALUN and 50 Ohm
termination may be required.
The frequency limits are those specified in the specification on page 4 of the
datasheet. Depending on the state of the Multiplier, Frequencies up to 400MHZ
can be used.