TDA7501_07 Datasheet, PDF (14/29 Pages) STMicroelectronics – Line driver for digital car radio Signal processor (DSPLD)

Description of the output part
TDA7501
Figure 11. Level diagram.
IN
2Vrms
4.15Vdc
INPUT PART
TDA7501
INPUT GAIN
0..15dB
1dB STEP
CODEC
INTERFACE
2Vrms
4.15Vdc
0.8Vrms
1.65Vdc
TDA7500
0.9Vrms
1.65Vdc
D00AU1205
OUTPUT PART
LEVEL
SELECT
GAIN
+6dB or
+12dB
VOLUME
+15
..
-79dB
2Vrms
4.15Vdc
OUTPUT
LINEDRIVERS
0/+6dB STEP
2Vrms (typ)
4.15Vdc
OUT
2Vrms
4.15Vdc
or
4Vrms
6Vdc
4.2
Speaker (linedriver) outputs
The Speaker outputs can be configured in three different operating modes:
1. - Internal reference mode with 0dB output gain,
2. - External reference mode with 0dB output gain
3. - External reference mode with 6dB output gain
Basically, in the internalreference mode the linedriver amplifier acts as a buffer with 0dB gain
regardless of the output gain programmed by bit D0. Since the buffer tracks the internal
generated reference, the OUTPUTREF pin may be left floating.
In the external reference mode the linedriver amplifiers reference tracks the voltage present
at the OUTPUTREF pin. This reference does not necessary have to be external to the
device, it can also be generated by invoking the VCC/2 divider inside the TDA7501 (bit
D1/6). In practice, the term external reference implied that the OUTPUTREF pin at least has
to connect to an external capacitor. In the external reference mode, an additional gain of
6dB can be added by assessing bit D0. This provides a nominal 4V_RMS output level in case
the TDA7501 is powered from a dual supply (V_DD = 8.3V). When fed from a single supply,
only 2.8V_RMS output level can be acheived.
For the programming of output gain and reference selection see the programming section.
Figure 12. Speaker (Linedriver) outputs simplified
from VOLUME-STAGE
2Vrms
4.15Vdc
D1/6
2R
R
3R
6dB
6dB
0dB
buffer
D0/6
V_REF
OUTPUTREF
V_REF
D1/6
6dB
+
-
D0/6
6dB
2R
R
3R
SPKROUT
D00AU1207
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