TDA7460ND(2009) View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

TDA7460ND
(Rev.:2009)

Car radio signal processor

STMicroelectronics 

Description of the audio processor part

TDA7460ND

4.1.2

Input stages

Most of the input circuits are the same as in preceding ST audioprocessors with exception of

the CD inputs (see Figure 4.).In the meantime there are some CD players in the market

having a significant high source impedance which affects strongly the common-mode

rejection of the normal differential input stage. The additional buffer of the CD input avoids

this drawback and offers the full common-mode rejection even with those CD players.

The TDA7460ND can be configured with an additional input; if the AC coupling before the

speaker stage is not used (bit 7 in subaddress 5 set to "1") ACINL and ACINR pins can be

used as an additional stereo input.

4.1.3 AutoZero

In order to reduce the number of pins there is no AC coupling between the In-Gain and the

t(s) following stage, so that any offset generated by or before the In-Gain stage would be

transferred or even amplified to the output.

uc To avoid that effect a special offset cancellation stage called AutoZero is implemented.To

d avoid audible clicks the audioprocessor is muted before the loudness stage during this time.

ro In some cases, for example if the µP is executing a refresh cycle of the I2C bus

P programming, it is not useful to start a new AutoZero action because no new source is

te selected and an undesired mute would appear at the outputs. For such applications the

TDA7460ND could be switched in the "Auto Zero Remain" mode (Bit 6 of the subaddress

le byte). If this bit is set to high, the DATABYTE 0 could be loaded without invoking the

so AutoZero and the old adjustment value remains.

Ob Figure 4. Input stages

) - CD

ct(s CDGND

duPHONE

100K

Pro PH_GND

te CASSETTE

ole AM

Obs MPX

100K

100K

15K

15K

15K

15K

15K

-

+

15K

15K

-

+

15K

STEREODECODER

IN GAIN

100K

D97AU633A

4.2

Mixing stage

This stage offers the possibility to mix the internal beep or the phone signal to any other

source. Due to the fact that the mixing stage is also located behind the In-Gain stage fine

adjustments of the main source level can be done in this way.

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