DS16EV5110A: interfacing Ethernet cable with AC coupled input

Hi:

    We need to transfer 4 channels 250Mbps data over 100 meter ethernet cable, it is required to use AC coupled in the signal chain.

    The transmitter is DS15BA101 and receiver is DS16EV5110A, so far we are able to recover 125MHz clock, but if we use prbs-7 data, then we can only go up to 62.5Mbps, it seems you have an evaluation board DS16EV51-AEVKC, which can support 225Mbps over more than 80 meters CAT5 UTP, I have below question:

     1: What is the difference between DS16EV5110 and DS16EV5110A ?

     2: Will ac-coupled interface degrade the equalizer performance ?

     3: For the input interface, is there a difference between 50 ohm single and 100 ohm differential impedance control  ?

      Thank you very much for your kindly help.

       Best regards!

       yifan