TDA7416_11 Datasheet, PDF (15/37 Pages) STMicroelectronics – Car radio signal processor

TDA7416
Description of the audio processor part
4.2.2
Single-ended stereo inputs
All single-ended inputs have an input impedance of 100 kΩ.
4.3
4.3.1
4.4
4.4.1
AutoZero
The AutoZero allows a reduction of the number of pins as well as external components by
canceling any offset generated by or before the In-Gain-stage (Please notice that externally
generated offsets, e.g. generated through the leakage current of the coupling capacitors,
are not canceled).
The auto-zeroing is started every time the DATA-BYTE 0 is selected and needs max. 0.3 ms
for the alignment. To avoid audible clicks the Audioprocessor have to be muted by soft-mute
or hard-mute during this time.
AutoZero remain
In some cases, for example if the µP is executing a refresh cycle of the IIC-Bus-
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 out-puts. For such applications the
TDA7416 could be switched in the AutoZero remain-mode (Bit 6(I1) 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.
Loudness
There are four parameters programmable in the loudness stage.
Attenuation
Figure 4 shows the attenuation as a function of frequency at f_P = 400 Hz
Figure 4. Loudness attenuation @ f_P = 400 Hz





D"





+
(Z
Doc ID 9837 Rev 2
+
'!0'03
15/37