TDA7410ND

Description of the audioprocessor part

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5

Description of the audioprocessor part

5.1

Input matrix

The input matrix of the TDA7410ND offers several possibilities to adapt the audioprocessor

to the desired application (see Figure 1). Into the standard application we have:

●

CD quasi differential

●

Cassette stereo

●

Phone

●

AM mono

●

Stereodecoder input

Figure 3.

Input Stage

5.2

AutoZero

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

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

transferred or even amplified to the output. To avoid that effect a special offset cancellation

stage called AutoZero is implemented. To avoid audible clicks the audioprocessor is muted

before the volume stage during this time. In some cases, for example if the P is executing a

refresh cycle of the I2C 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 outputs. For

such applications the TDA7410D could be switched in the "Auto Zero Remain" mode (Bit 6

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.

100K

CD

CDGND

-

+

D05AU1613

100K

100K

100K

STEREODECODER

IN GAIN

PHONE

AM

MPX

100K

100K

CASSETTE