Applications information

TDA7293

10/21

Doc ID 6744 Rev 8

4

Applications information

4.1

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.

Figure 7.

Slave function: pin 4 (Ref to pin 8)

Table 5.

Choosing alternative component values

Component

Suggested

value

Purpose

Larger than

suggested

Smaller than

suggested

R1 (1)

1.

R1 = R3 for pop optimization

22 k

Ω

Input resistance

Increase input

impedance

Decrease input

impedance

R2

680

Ω

Closed loop gain,

set to 30 dB (2)

2.

Closed loop gain has to be ³ 26dB

Decrease of gain

Increase of gain

R3 (1)

22 k

Ω

Increase of gain

Decrease of gain

R4

22 k

Ω

Standby time constant

Larger Standby

on/off time

Smaller standby

ON/OFF time; pop

noise

R5

10 k

Ω

Mute time constant

Larger mute

on/off time

Smaller mute

on/off time

C1

0.47

µF

Input DC decoupling

-

Higher low-frequency

cutoff

C2

22

µF

Feedback DC

decoupling

-

Higher low-frequency

cutoff

C3

10

µF

Mute time constant

Larger mute

on/off time

Smaller mute on/off

time

C4

10

µF

Standby time constant

Larger standby

on/off time

Smaller standby on/off

time; pop noise

C5

22

µF (3) x N

3.

Multiply this value by the number, N, of modular parts connected

Bootstrapping

-

Signal degradation at

low frequency

C6, C8

1000

µF

Supply voltage bypass -

-

C7, C9

0.1

µF

Supply voltage bypass -

Danger of oscillation

MASTER

UNDEFINED

SLAVE

-VS +3V

-VS +1V

-VS

D98AU821

Note:

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

3.9

Ω/2W and the capacitor is 1µF.