TDA7402_07 Datasheet, PDF (17/71 Pages) STMicroelectronics – Car radio signal processor

TDA7402
4
Audioprocessor part
Audioprocessor part
4.1
4.1.1
4.1.2
Input stages
In the basic configuration two full differential, two mono differential, one single ended stereo
and one single ended mono input are available. In addition a dedicated input for the stereo
decoder MPX signal is present.
Figure 3. Input-stages
SE2
FD1-
STEREO
100K
FD1+
100K
SE3
FD2-
STEREO
100K
FD2+
100K
SE4
MD1G
MONO
100K
MD1
SE4R
MD2G
MONO
100K
100K
MD2
100K
SE1
STEREO
100K
AM
MONO
100K
MPX
100K
15K 15K
1
-
+
1
15K 15K
15K 15K
1
-
+
1
15K 15K
28K
28K
-
+
28K
28K
SE4R
28K
28K
-
+
28K
28K
NOISE BLANKER
+
STEREO DECODER
MAIN SOURCE
SE3
SELECTOR
FD1/SE2
FD2
MD1/SE4
MUTE
MD2
SE1
100K
AM
FM
IN GAIN
MD2
MD1
FM
BEEP
MIXING
SELECTOR
MUTE
MIXING STAGE
SECOND SOURCE
SE3
SELECTOR
FD1/SE2
FD2
MD1/SE4
MUTE
MD2
SE1
AM
FM
IN GAIN
D00AU1142
Full-differential stereo Input 1 (FD1)
The FD1 input is implemented as a buffered full-differential stereo stage with 100kΩ input
impedance at each input. The attenuation is programmable in 3 steps from 0 to -12dB in
order to adapt the incoming signal level. A 6dB attenuation is included in the differential
stage, the additional 6dB are done by a following resistive divider. This input is also
configurable as two single ended stereo inputs (see pin-out).
Full-differential stereo Input 2 (FD2)
The FD2 input has the same general structure as FD1, but with a programmable attenuation
of 0 or 6dB embedded in the differential stage.
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