Datasheet

TAS5548
www.ti.com SLES270 –NOVEMBER 2012
For post-SRC 192-kHz data, the TAS5548 has two bass and treble tone controls. Each control has a ±18-
dB I
2
C control range with selectable corner frequencies and second-order slopes. These controls operate
two channel groups:
• L, R and C
• Sub
– Sub only has bass and no treble.
The bass and treble filters use a soft update rate that does not produce artifacts during adjustment.
Table 3-2. Bass and Treble Filter Selections
3-dB CORNER FREQUENCIES, Hz
f
S
FILTER SET 1 FILTER SET 2 FILTER SET 3 FILTER SET 4 FILTER SET 5
(kHz)
BASS TREBLE BASS TREBLE BASS TREBLE BASS TREBLE BASS TREBLE
88.2 115 2527 230 5053 345 8269 402 10106 459 11944
96 125 2750 250 5500 375 9000 438 11000 500 13000
176.4 230 5053 459 10106 689 16538 804 20213 919 23888
192 250 5500 500 11000 750 18000 875 22000 1000 26000
The I
2
C registers that control bass and treble are:
• Bass and treble bypass register (0x89–0x90, channels 1–8)
• Bass and treble slew rates (0xD0)
• Bass filter sets 1–5 (0xDA)
• Bass filter index (0xDB)
• Treble filter sets 1–5 (0xDC)
• Treble filter index (0xDD)
NOTE
The bass and treble bypass registers (0x89–0x90) are defaulted to the bypass mode. In
order to use the bass and treble, these registers must be in the inline (or enabled) mode for
each channel using bass and treble.
3.6 Volume, Automute, and Mute
The TAS5548 provides individual channel and master volume controls. Each control provides an
adjustment range of 18 dB to –127 dB in 0.25-dB increments. This permits a total volume device control
range of 36 dB to –127 dB plus mute. The master volume control can be configured to control six or eight
channels.
The TAS5548 has a master soft mute control that can be enabled by a terminal or I
2
C command. The
device also has individual channel soft mute controls that are enabled via I
2
C.
3.7 Loudness Compensation
The loudness compensation function compensates for the Fletcher-Munson loudness curves. The
TAS5548 loudness implementation tracks the volume control setting to provide spectral compensation for
weak low- or high-frequency response at low volume levels. For the volume tracking function, both linear
and logarithmic control laws can be implemented. Any biquad filter response can be used to provide the
desired loudness curve. The control parameters for the loudness control are programmable via the I
2
C
interface.
The TAS5548 has a single set of loudness controls for the eight channels. In 6-channel mode, loudness is
available to the six speaker outputs and also to the line outputs. The loudness control input uses the
maximum individual master volume (V) to control the loudness that is applied to all channels. In the 192-
kHz and 176.4-kHz modes, the loudness function is active only for channels 1, 2, and 8.
Copyright © 2012, Texas Instruments Incorporated TAS5548 DAP Architecture 23
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