HMC7044_Sysref Nshot


I am using HMC7044 & AD9695 and I've come across , and have a few questions,

1)"1shot sysref it must be DC coupled", why ?. Is it not possible to AC couple sysref for operating in N-shot mode using HMC7044?

2)"HMC can't work in LVDS mode for DC coupled 1shot sysref (known issue)".  I am unable to find anything mentioned like this in datasheet of HMC7044, Is there any errata for this ?

Thanks in advance,