TDA7501_07 Datasheet, PDF (13/29 Pages) STMicroelectronics – Line driver for digital car radio Signal processor (DSPLD)

TDA7501
4
Description of the output part
Description of the output part
The TDA7501 has 6 independent outputstage with volume control. The first 4 (main) outputs
have an input selector which allows to select besides the DAC outputs CD direct or
Phone/Navigation-mix. In addition one can mix the SPKR1 with Phone/Navigation so that
traffic or navigation announcements can bypass the DSP (see figure 8).
The TDA7500 CODEC outputs have a maximum output voltage of 0.5Vrms . To obtain
4Vrms , (in the dual supply mode only) the signal is first amplified to have a reference
amplitude of 2V rms. The following volume stage offers up to 15dB gain which gives along
with the programmable 6dB gain in the output-stage enough overdrive capability. To achieve
the maximum output swing of 4Vrms the device must be supplied with an additional supply
of 12V. With a single supply (V_dd = V_CC = 8.3V) 2.8Vrms are obtained at the output at
maximum.
Figure 10. Output part.
4.1
Overall gain structure
The overall gain structure of the TDA7501 can be shown in its target application together
with the V225.
The output part in level select (D6/4) offers an additional adaption to the DSP's output level
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