TDA7402 STMicroelectronics, TDA7402 Datasheet - Page 18

• Manufacturer Part Number: TDA7402
• Description: IC PROCESSOR CAR SIGNAL 44-LQFP
• Manufacturer: STMicroelectronics
• Type: Car Signal Processorr

Specifications of TDA7402

• Applications: Automotive Systems
• Mounting Type: Surface Mount
• Package / Case: 44-LQFP
• Case: QFP
• Dc: 05+
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Audioprocessor part
3.3.2
3.4
3.4.1
3.4.2
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The root cause of this procedure is, that after muting the stereo decoder (Step 1), the
internal stereo decoder filters have to settle in order to perform a proper offset cancellation.
AutoZero remain
In some cases, for example if the µP is executing a refresh cycle of the I
programming, it is not useful to start a new AutoZero action because no new source is
selected and an undesired mute would appear at the outputs. For such applications the
TDA7402 could be switched in the AutoZero Remain Mode (Bit 6 of the subaddress byte).
If this bit is set to high, the DATABYTE 0 could be loaded without invoking the AutoZero and
the old adjustment value remains.
Pause detector / MUX-output
The pin number 40 (Pause/MUX) is configurable for two different functions:
1.
2.
Loudness
There are four parameters programmable in the loudness stage:
Attenuation
Figure 4
Figure 4.
During pause detector OFF this pin is used as a mono output of the main input selector.
This signal is often used to drive a level/equalizer display on the car radio front panel.
During pause detector ON the pin is used to define the time constant of the detector by
an external capacitor. The pause detector is driven by the internal stereo decoder
outputs in order to use pauses in the FM signal for alternate frequency jumps. If the
signal level of both stereo decoder channels is outside the programmed voltage
window, the external capacitor is abruptly discharged. Inside the pause condition the
capacitor is slowly recharged by a constant current of 25µA. The pause information is
also available via I
dB
-10.0
-15.0
-20.0
-25.0
-5.0
0.0
shows the attenuation as a function of frequency at f
10.0
Loudness attenuation @ f
2
C Bus (see I
100.0
2
C Bus programming).
P
= 400Hz.
Hz
1.0K
P
= 400Hz
2
C Bus
10.0K
TDA7402