TDA7719 datasheet(18/45 Pages) STMICROELECTRONICS

18 / 45 page

Description

TDA7719

18/45

4.3.4

Flat mode

In flat mode the loudness stage works as a 0dB to -15dB attenuator.

4.4

SoftMute

The digitally controlled SoftMute stage allows muting/demuting the signal with a I2C-bus

programmable slope. The mute process can either be activated by the SoftMute pin or by

the I2C-bus. This slope is realized in a special S-shaped curve to mute slow in the critical

regions (see Figure 8).

For timing purposes the Bit0 of the I2C-bus output register is set to 1 from the start of muting

until the end of demuting.

Figure 8.

Softmute timing

Note:

A started Mute action is always terminated and could not be interrupted by a change of the

mute signal

4.5

SoftStep volume

When the volume-level is changed audible clicks could appear at the output. The root cause

of those clicks could either be a DC Offset before the volume-stage or the sudden change of

the envelope of the audio signal. With the SoftStep feature both kinds of clicks could be

reduced to a minimum and are no more audible. The blend-time from one step to the next is

programmable as 5ms or 10ms. The softstep control is described in detail in Chapter 4.10.

4.6

Bass

There are four parameters programmable in the bass stage:

EXT.

MUTE

+SIGNAL

REF

-SIGNAL

2C BUS

OUT

Time

D97AU634

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