Application suggestion

TDA2004R

12/17

Doc ID 17614 Rev 1

3

Application suggestion

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

Figure 2. Different values can be used; the following table can help the designer.

3.1

Built-in protection systems

3.1.1

Load dump voltage surge

The TDA2004R has a circuit which enables it to withstand voltage pulse train, on Pin 9, of

the type shown in Figure 20. If the supply voltage peaks to more than 40 V, then an LC filter

must be inserted between the supply and pin 9, in order to assure that the pulses at pin 9

will be held within the limits shown.

A suggested LC network is shown in Figure 19. With this network, a train of pulses with

amplitude up to 120 V and width of 2 ms can be applied at point A. This type of protection is

ON when the supply voltage (pulse or DC) exceeds 18 V. For this reason the maximum

operating supply voltage is 18 V.

Table 5.

Recommended values of the component of the application circuit

Component

Recommended

value

Purpose

Larger than

Smaller than r

R1

120 k

Ω

Optimization of the

output signal symmetry

R2, R4

1 k

Ω

Closed loop gain setting

(1)

Increase of gain

Decrease of gain

R3, R5

3.3

Ω

Decrease of gain

Increase of gain

R6, R7

1

Ω

Frequency stability

Danger of oscillation

at high frequency with

inductive load

C1, C2

2.2

μF

Input DC decoupling

High turn-on delay

High turn-on pop, higher

low frequency cutoff.

Increase of noise

C3

10

μF

Ripple rejection

Increase of SVR,

Increase of the switch-on

time

Degradation of SVR

C4, C6

100

μF

Bootstrapping

-

Increase of distortion at

low frequency

C5, C7

100

μF

Feedback input DC

decoupling

--

C8, C9

0.1

μF

Frequency stability

-

Danger of oscillation

C10, C11

1000 to 2200

μF

Output DC decoupling

-

Higher low-frequency

cut-off

1.

The closed loop gain must be higher than 26 dB.