Before revision: A 1-bit DAC (sometimes called Bitstream converter by Philips) is used as a consumer electronics marketing term describing an oversampling digital-to-analog converter (DAC) that utilizes a digital noise shaping delta-sigma modulator operating at many multiples of the sampling frequency that outputs to an actual 1-bit DAC (which could be fully differential to minimize crosstalk).
After revision: A 1-bit DAC (sometimes called Bitstream converter by Philips) is used as a consumer electronics marketing term describing an oversampling digital-to-analog converter (DAC) that uses a digital noise shaping delta-sigma modulator operating at many multiples of the sampling frequency that outputs to an actual 1-bit DAC (which could be fully differential to minimize crosstalk).