TDA7404DTR Datasheet, PDF (16/35 Pages) STMicroelectronics – Car radio signal processor

Description of functionality
TDA7404
4.4.3
Low and high frequency boost
Figure 7 shows the different Loudness-shapes in low & high frequency boost.
Figure 7. Loudness attenuation, f_C = 2.4 kHz
5
0
-5
- 10
- 15
- 20
10
100
1K
10K
4.5
Soft-mute
The digitally controlled soft-mute stage allows muting/demuting the signal with a I²C bus
programmable slope. The mute process can either be activated by the Mute pin or by the
I²C bus. This slope is realized in a special S-shaped curve to mute slow in the critical
regions (seeFigure 6).
For timing purposes the Bit 0 of the I²C bus output register is set to 1 from the start of
muting until the end of de-muting.
Figure 8. Soft-mute timing
1. Please notice that a started Mute-action is always terminated and could not be interrupted by a change of
the mute -signal.
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