The MAX5190 is a VOLTAGE output DAC because of the internal termination resistors. The variable signal is generated as a current, but due to the high (400 ohm) termination resistor, the DAC must be used as a voltage output device with a high source impedance rather than as a true low impedance source.
Users also can use a high-speed operational amplifier to convert the differential voltage into a single-ended voltage.
For example, the attached circuit produces the 0 to -4V swing based on the MAX5190 DAC. The output of this circuit will swing from 0V (all 0’s at DAC input) to -4V (all 1’s at DAC input).