STA7360

Application hints

Doc ID 9814 Rev 4

23/28

6

Application hints

This section explains briefly how to get the best from the STA7360 and presents some

application circuits with suggestions for the value of the components. These values can

change depending on the characteristics that the designer of the car radio wants to obtain,

or other parts of the car radio that are connected to the audio block.

To optimize the performance of the audio part it is useful (or indispensable) to analyze also

the parts outside this block that can have an interconnection with the amplifier.

This method can provide components and system cost savings.

6.1

Reducing turn-on/off pop

The STA7360 has been designed in a way that the turn-on (off) transients are controlled

through the charge (discharge) of the Csvr capacitor.

As a result of it, the turn-on (off) transient spectrum contents is limited only to the subsonic

range. The following section gives some brief notes to get the best from this design feature

(it will refer mainly to the stereo application which appears to be in most cases the more

critical from the pop viewpoint. The bridge connection in fact, due to the common-mode

waveform at the outputs, does not give a pop effect).

6.2

Turn-on

Figure 36 shows the output waveform (before and after the "A" weighting filter) compared to

the value of Csvr.

Better pop-on performance is obtained with higher Csvr values (the recommended range is

from 22 µF to 220 µF).

The turn-on delay (during which the amplifier is in mute condition) is essentially a function of

Cout, Csvr:

T1

≈ 120 • C

out

T2

≈ 1200 • C

svr

The turn-on delay is given by:

T1+T2 STEREO

T2 BRIDGE

The best performance is obtained by driving the st-by pin with a ramp having a slope slower

than 2 V/ms.

Obsolete

Product(s)

- Obsolete

Product(s)