TDA7462 Datasheet, PDF (10/25 Pages) STMicroelectronics – DUAL AUDIOPROCESSOR WITH COMPANDER AND SUBWOOFER OUTPUT

TDA7462
Figure 3. Loudness Attenuation @ fc = 400Hz
(second order)
0.0
-5.0
-10.0
grammable slope. The mute process can either
be activated by the SoftMute pin(SM) or by the
I²C bus. This slope is realized in a special S-
shaped curve to mute slow in the critical regions
(see Figure 6).
For timing purposes the Bit 3 of the I²C bus out-
put register is set to 1 from the start of muting un-
til the end of de-muting.
Figure 6. Softmute Timing
-15.0
-20.0
10.0
100.0
1.0K
10.0K
Figure 4. Loudness Center frequency @ Attn.
= 15dB (second order)
0.0
-5.0
-10.0
-15.0
-20.0
10.0
100.0
1.0K
10.0K
Figure 5. Loudness @ Attn. = 15dB, fc = 400Hz
(dB)
D98AU844
-5
-10
-15
-20
10
100
1,000
Hz
SoftMute
The digitally controlled SoftMute stage allows
muting/de-muting the signal with a I²C bus pro-
1
EXT.
MUTE
+SIGNAL
REF
-SIGNAL
1
I²C BUS
OUT
D97AU634
Time
Note: Please notice that a started Mute action is always terminated
and could not be interrupted by a change of the mute signal.
SoftStep Volume
When the volume level is changed audible clicks
could appear at the output. The root cause of
those clicks could either be a DC offset before
the volume stage or the sudden change of the
envelope of the audio signal. With the SoftStep
feature both kinds of clicks could be reduced to a
minimum and are no more audible. The blend
time from one step to the next is programmable in
four steps.
Figure 7. Soft Step Timing
VOUT
2dB
1dB
-1dB
-2dB
10ms
Time
D97AU635
Note: For steps more than 1dB the softstep mode should be
deactivated because it could generate a 1dB error during the
blend-time
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