AD9467 FMC voltage level

I have an issue with using the AD9467 FMC + FPGA reference design seems to be 1v=100 and 0.5v=50. Figure 1 below shows the signal that captures using 1Vp-p with 25 kHz that mean its multiply by 100 times. My system has to work with a low voltage between 2 to 20mV.
How do I change the gain? Please help.

Figure 1: sinewave signal 1vp-p, 25 KHz