TDA7412 Datasheet, PDF (11/56 Pages) STMicroelectronics – CARRADIO SIGNAL PROCESSOR

TDA7412
1.0 DESCRIPTION OF THE AUDIOPROCESSOR PART
1.1 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 stereodecoder MPX-signal is present.
Figure 1. 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
SE1
STEREO
AM
MONO
100K
100K
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 divid-
er. 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 em-
bedded in the differential stage.
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