TDA7416 Datasheet, PDF (11/27 Pages) STMicroelectronics – CARRADIO SIGNAL PROCESSOR

TDA7416
1.4 SoftMute
The digitally controlled SoftMute stage allows muting/demuting the signal with a I²C-bus programmable
slope. The mute process can either be activated by the SoftMute pin or by the I²C-bus. This slope is real-
ized in a special S-shaped curve to mute slow in the critical regions (see Figure 5).
For timing purposes the Bit0 of the I²C-bus output register is set to 1 from the start of muting until the end
of de-muting.
Figure 5. Soft Mute-Timing
Note: Please notice that a started Mute-action is always terminated and could not be interrupted by a change of the mute -signal.
1.5 SoftStep Volume and Speaker
When the speaker-level is changed audible clicks could appear at the output. The root cause of those
clicks could either be a DC-Offset before the speaker-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 6. SoftStep-Timing for Volume
1dB
0.5dB
-0.5dB
SS Time
-1dB
Note: For steps more than 0.5dB (Volume) or 1dB (Speaker) the SoftStep mode should be deactivated because it could generate a hard 1dB
step during blending.
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