TDA7350A Datasheet, PDF (16/22 Pages) STMicroelectronics – 22W BRIDGE-STEREO AMPLIFIER FOR CAR RADIO

TDA7350A
APPLICATION HINTS
This section explains briefly how to get the best
from the TDA7350A and presents some applica-
tion circuits with suggestions for the value of the
components.Thesevalues can change depending
on the characteristics that the designer of the car
radio wants to obtain,or other parts of the car ra-
dio 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 interconnec-
tion with the amplifier.
This method can provide components and system
cost saving.
Figure 39:
a) Csvr = 22 µF
Reducing Turn On-Off Pop
The TDA7350A 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 spec-
trum 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,doesnot give pop effect).
b) C_svr = 47 µF
TURN-ON
Fig. 39 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 22uF to 220uF).
The turn-on delay (during which the amplifier is in
mute condition) is a function essentially of : Cout ,
C_svr .
Being:
T1 ≈ 120 • Cout
T2 ≈ 1200 • C_svr
c) Csvr = 100 µF
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
2V/ms
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