TDA1904
APPLICATION SUGGESTION
The recommended values of the external compo-
nents are those shown on the application circuit of
fig. 1.
When the supply voltage VS is less than 6V, a 68Ω
resistor must be connected between pin 2 and pin
3 in order to obtain the maximum output power.
Different values can be used. The following table
can help the designer.
Components
Recomm.
value
Purpose
Larger than
Smaller than
Allowed range
recommended value recommended value
Min. Max.
R1
10 KΩ
Increase of gain.
Decrease of gain.
9R3
Increase quiescent
Feedback resistors
current.
R2
100 Ω
Decrease of gain.
Increase of gain.
1 KΩ
R3
4.7 Ω Frequency stability Danger of oscillation at
high frequencies with
inductive loads.
R4
68 Ω Increase of the
output swing with
low supply voltage.
39 Ω 220 Ω
C1
2.2 µF Input DC
decoupling.
Higher cost lower
noise.
Higher low
frequency cutoff.
Higher noise.
C2
0.1 µF Supply voltage
bypass.
Danger of
oscillations.
C3
22 µF Ripple rejection
Increase of SVR
Degradation of SVR. 2.2 µF 100ΩF
increase of the
switch-on time.
C4
2.2 µF Inverting input DC
Increase of the
Higher low
0.1 ΩF
decoupling.
switch-on noise
frequency cutoff.
C5
47 µF Bootstrap.
Increase of the
distortion at low
frequency.
10 µF 100µF
C6
0.22 µF Frequency stability.
Danger of oscillation.
C7
1000 µF Output DC
decoupling
Higher low
frequency cutoff.
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