TDA7293_10 Datasheet, PDF (10/21 Pages) STMicroelectronics – 120-volt, 100-watt, DMOS audio amplifier with mute and standby

Applications information
4
Applications information
TDA7293
4.1
10/21
Applications suggestions
The recommended values of the external components are those shown on the application
circuit of Figure 1 on page 1. Different values can, however, be used and the following table
could be useful when choosing alternative values.
Table 5. Choosing alternative component values
Component
Suggested
value
Purpose
Larger than
suggested
R1 ⁽¹⁾
R2
R3 ⁽¹⁾
22 kΩ
680 Ω
22 kΩ
Input resistance
Closed loop gain,
set to 30 dB ⁽²⁾
Increase input
impedance
Decrease of gain
Increase of gain
R4
22 kΩ
Standby time constant
Larger Standby
on/off time
R5
10 kΩ
Mute time constant
Larger mute
on/off time
C1
0.47 µF
Input DC decoupling -
C2
22 µF
Feedback DC
decoupling
-
C3
10 µF
Mute time constant
Larger mute
on/off time
C4
10 µF
Standby time constant
Larger standby
on/off time
C5
22 µF ⁽³⁾ x N Bootstrapping
-
C6, C8
1000 µF
Supply voltage bypass -
C7, C9
0.1 µF
Supply voltage bypass -
1. R1 = R3 for pop optimization
2. Closed loop gain has to be ³ 26dB
3. Multiply this value by the number, N, of modular parts connected
Smaller than
suggested
Decrease input
impedance
Increase of gain
Decrease of gain
Smaller standby
ON/OFF time; pop
noise
Smaller mute
on/off time
Higher low-frequency
cutoff
Higher low-frequency
cutoff
Smaller mute on/off
time
Smaller standby on/off
time; pop noise
Signal degradation at
low frequency
-
Danger of oscillation
Figure 7. Slave function: pin 4 (Ref to pin 8)
-V_S +3V
-V_S +1V
-V_S
MASTER
Note:
UNDEFINED
SLAVE
D98AU821
If in the application the speakers are
connected via long wires, it is a good rule
to add, between the output and GND, a
boucherot cell in order to avoid dangerous
spurious oscillations if the speakers
terminal are shorted.
The suggested boucherot resistor is
3.9Ω/2W and the capacitor is 1µF.
Doc ID 6744 Rev 8