The Differential Input-Logic High and Low values mentioned in the MAX5877 datasheet are the MAX and MIN threshold level of the logic input, as in the MAX and MIN logic threshold for the interpretation of logic HIGH and LOW on the LVDS input. If the LVDS logic inputs are driven above 100mV for logic high and below -100mV for logic low, the input is guaranteed to have passed that threshold for any threshold level variability that may be seen in the MAX5877. These values mentioned in the datasheet are not the maximum voltage input for a logic high nor the minimum for logic low. The absolute maximum rating for these LVDS input pins are -0.3V to (DV DD1.8 + 0.3V) as mentioned in the datasheet.