Clock Generation and Distribution (AD9577)

Hi,

I want to generate and to distribute 128MHz clock to ADC/DAC(AD9707,AD9251). (I need 3-LVDS and 1-CMOS outputs)

I'm using AD9577.

Ref clock is SINE=26MHz (50 ohm 0dBm from OCXO)

OUTPUT clock LVDS=128MHZ (CMOS=128MHz as an option).

Questions:

1. Can I provide a Sine ref clock to AD9577 or should it be "square wave"?
2. My ref clock source is 50 ohm--> 0dBm, and AD9577 refclk input requires 2V for "1", how can I know the internal resistance of REFCLK port?
   I want to be sure 0dBm@50ohm is enough (0dBm=1mW, 1mW=50*Vout*Vout, Vout=SQRT{1mW/50}=4.5mV@50ohm at Ref clock output).

Thank you.