LA4814V

No.A0972-6/17

5.Second amplifier control function (only when BTL mode is used)

The second amplifier control function is a function to reduce the startup pop-noise in BTL mode. The pop noise can be

reduced by first turning on the IC while the second amplifier is stopped, then after the potential inside the IC gets

stabilized, turning on the second amplifier.

The values shown below are recommended for the control time.

C5 [

μF]

2.2

3.3

4.7

10

Twu [ms]

200

250

300

500

* Twu : Time after releasing standby to second amplifier turn-on

a) When using microcomputer control

The second amplifier can be controlled by applying the following voltages to pin 9.

Second amplifier operation mode … V9

≤ 0.3V

Second amplifier stop mode … V9

≥ 1.6V

However, set the resistance value of the resistor R6 inserted in series in such a way that the condition in the following

formula is met.

R6

≤ 16.2 × (Vcnt - 1.6) kΩ

The pin 9 injected current is expressed by the following formula :

I9 = (57.6

× Vcnt - 31.7)/(1+0.058 × R6) μA

Fig. 3

b) When microcomputer control is not possible

When the microcomputer cannot be used, the second amplifier can be controlled by adding the external components

as shown in Fig. 4.

VCC (V)

5

3.6

3

R7 (k

Ω)

10

6.8

6.8

R9 (k

Ω)

120

68

56

C8 (

μF)

100

100

100

Fig. 4

6.Shorting between pins

When power is applied with pins left short-circuited, electrical deterioration or damage may result.

Therefore, check before power application if pins are short-circuited with solder, etc. during mounting of IC.

7.Load shorting

If the load is left short-circuited for a long period of time, electrical deterioration or damage may occur.

Never allow the load to short-circuit.

8.Maximum rating

When IC is used near the maximum rating, there is a possibility that the maximum rating may be exceeded even under

the smallest change of conditions, resulting in failure. Take sufficient margin for variation of supply voltage and use IC

within a range where the maximum rating will never be exceeded.

Vcnt

CNT

R6

V9

9

+

R7

C8

R5

R9

VCC

VCC

CNT

STBY

14

9

8