E-TDA7406 STMicroelectronics, E-TDA7406 Datasheet - Page 20

• Manufacturer Part Number: E-TDA7406
• Description: Audio DSPs CAR RADIO SIGNAL
• Manufacturer: STMicroelectronics

Specifications of E-TDA7406

• Operating Temperature Range: - 40 C to + 85 C
• Mounting Style: SMD/SMT
• Package / Case: TQFP-44
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Description of the audioprocessor part
4.4
Note:
4.5
4.5.1
4.5.2
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Soft Mute
The digitally controlled Soft Mute stage allows signal muting/demutingwith a programmable
slope. The Mute time is selectable among 4 values: 0.48, 0.96, 123 and 324ms. The mute
process can either be activated by the Soft Mute pin or via the I
in a special S-shaped curve to mute slow in the critical regions (see
For timing purposes the I
of muting until the end of de-muting.
Figure 7.
Please notice that a started Mute-action is always terminated and could not be interrupted
by a change of the mute -signal.
Volume Control
Gain/Attenuation Control
The volume control can range from a gain of 32dB up to an attenuation of 79dB; however it
is not recommended to use a gain higher than 20dB for performance reasons.
Soft Step Volume
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 with four different values: 320μs, 1.28ms, 5.12ms and 20.4ms.
Soft Mute-Timing
2
C-bus output register (Bit0 = SM read bit) is set to 1 from the start
2
C-bus. This slope is realized
Figure
7).
TDA7406