The PCM1753 device includes two independent output channels, VOUTL and VOUTR. These are unbalanced outputs, each capable of driving 4 VPP typical into a 5-kΩ ac-coupled load. The internal output amplifiers for VOUTL and VOUTR are biased to the dc common-mode (or bipolar zero) voltage, equal to 0.5 VCC.
The output amplifiers include an RC continuous-time filter, which helps to reduce the out-of-band noise energy present at the DAC outputs due to the noise shaping characteristics of the PCM1754 delta-sigma D/A converters. The frequency response of this filter is shown in Figure 24. By itself, this filter is not enough to attenuate the out-of-band noise to an acceptable level for many applications. An external low-pass filter is required to provide sufficient out-of-band noise rejection. Further discussion of DAC post-filter circuits is provided in the Applications Information section of this data sheet.