APPLICATION SUGGESTIONS (see Test and Application Circuits of the Fig. 1)

The recommended values of the external components are those shown on the application circuit of Fig-

ure 1. Different values can be used; the following table can help the designer.

COMPONENTS

SUGGESTED VALUE

PURPOSE

LARGER THAN

SUGGESTED

SMALLER THAN

SUGGESTED

R1 (*)

22k

INPUT RESISTANCE

INCREASE INPUT

IMPEDANCE

DECREASE INPUT

IMPEDANCE

R2

680

Ω

CLOSED LOOP GAIN

SET TO 30dB (**)

DECREASE OF GAIN INCREASE OF GAIN

R3 (*)

22k

INCREASE OF GAIN

DECREASE OF GAIN

R4

22k

ST-BY TIME

CONSTANT

LARGER ST-BY

ON/OFF TIME

SMALLER ST-BY

ON/OFF TIME;

POP NOISE

R5

10k

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

ST-BY TIME

CONSTANT

LARGER ST-BY

ON/OFF TIME

SMALLER ST-BY

ON/OFF TIME;

POP NOISE

C5

22

µFXN (***)

BOOTSTRAPPING

SIGNAL

DEGRADATION AT

LOW FREQUENCY

C6, C8

1000

µF

SUPPLY VOLTAGE

BYPASS

C7, C9

0.1

µF

SUPPLY VOLTAGE

BYPASS

DANGER OF

OSCILLATION

(*) R1 = R3 for pop optimization

(**) Closed Loop Gain has to be

≥ 26dB

(***) Multiplay this value for the number of modular part connected

MASTER

UNDEFINED

SLAVE

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 when the

speakers terminal are shorted.

The suggested Boucherot Resistor is 3.9

Ω/2W

and the capacitor is 1

µF.

TDA7293

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