TLV320DAC3101_15 Datasheet, PDF (37/100 Pages) Texas Instruments – Low-Power Stereo Audio DAC With Audio Processing and Stereo Class-D Speaker Amplifier

TLV320DAC3101
www.ti.com
SLAS666A – JANUARY 2010 – REVISED MAY 2012
5.5.4.4 DRC Attack Rate
When the output of the DAC digital volume control exceeds the programmed DRC threshold, the gain
applied in the DAC digital volume control is progressively reduced to avoid the signal from saturating the
channel. This process of reducing the applied gain is called attack. To avoid audible artifacts, the gain is
reduced slowly with a rate equaling the attack rate, programmable via page 0 / register 70, bits D7–D4.
Attack rates can be programmed from 4-dB gain change per sample period to 1.2207e–5-dB gain change
per sample period.
Attack rates should be programmed such that before the output of the DAC digital volume control can clip,
the input signal should be sufficiently attenuated. High attack rates can cause audible artifacts, and too-
slow attack rates may not be able to prevent the input signal from clipping.
The recommended DRC attack rate value is 1.9531e–4 dB per sample period.
5.5.4.5 DRC Decay Rate
When the DRC detects a reduction in output signal swing beyond the programmed DRC threshold, the
DRC enters a decay state, where the applied gain in the digital-volume control is gradually increased to
programmed values. To avoid audible artifacts, the gain is slowly increased with a rate equal to the decay
rate programmed through page 0 / register 70, bits D3–D0. The decay rates can be programmed from
1.5625e–3 dB per sample period to 4.7683e–7 dB per sample period. If the decay rates are programmed
too high, then sudden gain changes can cause audible artifacts. However, if it is programmed too slow,
then the output may be perceived as too low for a long time after the peak signal has passed.
The recommended value of DRC decay rate is 2.4414e–5 dB per sample period.
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