The impedance at the pin (-) is of the order of 100

Ω,

while that of the pin (+) is very high, which is also

what was wanted.

C1 = C2 = C3

R1

R2

R3

22 nF

8.2 k

Ω

5.6 k

Ω

33 k

Ω

using a Bessel 3rd order Sallen and Key structure

are :

In the block diagram of Figure 21 is represented an

active loudspeaker system completely realized us-

ing power integrated circuit, rather than the tradi-

tional discrete transistors on hybrids, very high

quality is obtained by driving the audio spectrum

into three bands using acti ve cro ssove rs

(TDA2320A) and a separate amplifier and loud-

speakers for each band.

A modern subwoofer/midrange/tweeter solution is

used.

PRATICAL CONSIDERATION

Printed Circuit Board

The layout shown in Figure 11 should be adopted

by the designers. If different layouts are used, the

ground points of input 1 and input 2 must be well

decoupled from the gorund return of the output in

which a high current flows.

Assembly Suggestion

No electrical isolation is needed between the pack-

age and the heatsink with single supply voltage

configuration.

Application Suggestions

The recommended values of the components are

those shown on application circuit of Fig. 10. Dif-

ferent values can be used. The following table can

help the designer.

Figure 21 : High Power Active Loudspeaker System using TDA2030A and TDA2040

Comp.

Recom.

Value

Purpose

Larger than

Recommended Value

Smaller than

Recommended Value

R1

22k

Ω

Non inverting input biasing

Increase of input impedance

Decrease of input impedance

R2

680

Ω

Closed loop gain setting

Decrease of gain (*)

Increase of gain

R3

22k

Ω

Closed loop gain setting

Increase of gain

Decrease of gain (*)

R4

4.7

Ω

Frequency stability

Danger of oscillation at high

frequencies with inductive loads

C1

1

µF

Input DC decoupling

Increase of low frequencies cut-off

C2

22

µF

Inverting DC decoupling

Increase of low frequencies cut-off

C3, C4

0.1

µF

Supply voltage bypass

Danger of oscillation

C5, C6

220

µF

Supply voltage bypass

Danger of oscillation

C7

0.1

µF

Frequency stability

Danger of oscillation

(*) The value of closed loop gain must be higher than 24dB

TDA2040

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