Datasheet

PCM3070
www.ti.com SLAS724 – FEBRUARY 2011
DAC
The PCM3070 includes a stereo audio DAC supporting data rates from 8kHz to 192kHz. Each channel of the
stereo audio DAC consists of a signal-processing engine with fixed processing blocks, a programmable miniDSP,
a digital interpolation filter, multi-bit digital delta-sigma modulator, and an analog reconstruction filter. The DAC is
designed to provide enhanced performance at low sampling rates through increased oversampling and image
filtering, thereby keeping quantization noise generated within the delta-sigma modulator and signal images
strongly suppressed within the audio band to beyond 20kHz. To handle multiple input rates and optimize
performance, the PCM3070 allows the system designer to program the oversampling rates over a wide range
from 1 to 1024. The system designer can choose higher oversampling ratios for lower input data rates and lower
oversampling ratios for higher input data rates.
The PCM3070 DAC channel includes a built-in digital interpolation filter to generate oversampled data for the
sigma-delta modulator. The interpolation filter can be chosen from three different types depending on required
frequency response, group delay and sampling rate.
The DAC path of the PCM3070 features many options for signal conditioning and signal routing:
• 2 headphone amplifiers
– Usable in single-ended or differential mode
– Analog volume setting with a range of -6 to +29 dB
• 2 line-out amplifiers
– Usable in single-ended or differential mode
– Analog volume setting with a range of -6 to +29 dB
• Digital volume control with a range of -63.5 to +24dB
• Mute function
• Dynamic range compression (DRC)
In addition to the standard set of DAC features the PCM3070 also offers the following special features:
• Built in sine wave generation (beep generator)
• Digital auto mute
• Adaptive filter mode
DAC Processing Blocks — Overview
The PCM3070 implements signal processing capabilities and interpolation filtering via processing blocks. These
fixed processing blocks give users the choice of how much and what type of signal processing they may use and
which interpolation filter is applied.
Table 10 gives an overview over all available processing blocks of the DAC channel and their properties. The
Resource Class Column (RC) gives an approximate indication of power consumption.
The signal processing blocks available are:
• First-order IIR
• Scalable number of biquad filters
• 3D – Effect
• Beep Generator
The processing blocks are tuned for typical cases and can achieve high image rejection or low group delay in
combination with various signal processing effects such as audio effects and frequency shaping. The available
first-order IIR and biquad filters have fully user-programmable coefficients. The Resource Class Column (RC)
gives an approximate indication of power consumption.
Table 10. Overview – DAC Predefined Processing Blocks
Processing Interpolation Channel 1st Order Num. of DRC 3D Beep Resource
Block No. Filter IIR Available Biquads Generator Class
PRB_P1
(1)
A Stereo No 3 No No No 8
PRB_P2 A Stereo Yes 6 Yes No No 12
(1) Default
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Product Folder Link(s): PCM3070