Texas Instruments ADC - Input Clock
The ADCs Vcm = 1.7V, is this the in and output Vcm?

Vcm is an output voltage and can be used to bias the clock inputs if only a single ended clock is used (see figure 64 below). The clock signal is then fed via a capacitor. For full differential clocks you don't need to bias (figure 65): -


Is it possible to clock the ADC with a Vpp = 700mV and Vcm = 1V?

I don't believe that would work.