PRODUCT OVERVIEW

ANALOG OUTPUTS

VOLTAGE REFERENCE VCOM

PCM1789

The PCM1789 is a high-performance stereo DAC targeted for consumer audio applications such as Blu-ray Disc

players and DVD players, as well as home multi-channel audio applications (such as home theater and A/V

receivers). The PCM1789 consists of a two-channel DAC. The DAC output type is fixed with a differential

formats, and 24-bit linear PCM input data in right-justified and DSP formats with various sampling frequencies

SPI software, and hardware.

The PCM1789 includes a two-channel DAC, with a pair of differential voltage outputs pins. The full-scale output

load, if the load resistance conforms to the specification. These balanced outputs are each capable of driving 0.8

amplifiers for VOUTL and VOUTR are biased to the dc common voltage, equal to 0.5 VCC1.

The output amplifiers include an RC continuous-time filter that helps to reduce the out-of-band noise energy

present at the DAC outputs as a result of the noise shaping characteristics of the PCM1789 delta-sigma (

ΔΣ)

DACs. The frequency response of this filter is shown in the Analog Filter Characteristic (Figure 10) of the Typical

Characteristics. By itself, this filter is not enough to attenuate the out-of-band noise to an acceptable level for

most 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 Application Information section.

The PCM1789 includes a pin for the common-mode voltage output, VCOM. This pin should be connected to the

analog ground via a decoupling capacitor. This pin can also be used to bias external high-impedance circuits, if

they are required.

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