All of ADI’s high speed, high performance DDSs incorporate DACs with current rather than voltage outputs. Generally, the DAC has a balanced output comprised of two pins. The “normal” pin produces an output based on a positive scale factor, while the “complementary” pin produces an output based on a negative scale factor. When a digital sinusoid drives the input to the DAC, the result is a balanced output signal. See Analog Devices’ Application Note AN-912.