LA4814V

No.A0972-7/17

9.Turn-off transient response characteristics

If the IC is turned off and then turned back on while there is a potential difference between the pin 7 (reference voltage,

plus input pin) and pins 5 and 10 (minus input pins), a louder pop noise than the one normally generated when power is

switched on will be emitted. Therefore, in order to minimize the turn-on pop noise, smoothen the discharge of the input

and output capacitors, and bring the potential of pin 7 and pins 5 and 10 to approximately the same level, then turn on

the IC.

a) Single ended mode

When the continuous changeover of mode between standby and operation is necessary, it is recommended to insert a

resistor between the output pins (pins 3 and 12) and ground to accelerate the turn-off transient response characteristic.

The value shown below is recommended for the resistor used for discharge. In order to reduce pop noise, it is

recommended that time necessary for turning the IC back on is greater than the following value.

Recommended discharge resistor : R = 4.7k

Ω

(Recommended turn-on time : T = 600ms)

b) BTL mode

When the continuous changeover of mode between standby and operation is performed, it is recommended that the

second amplifier control function be used to reduce the turn-on pop noise. If this function is used, the pop noise level

can be reduced regardless of the time taken for the IC to turn on after it is turned off.

For details on the time taken for the second amplifier to turn on after the IC is turned on, refer to Section 5 “Second

amplifier control function.”

PWR

STBY

100ms/div

OUT:50mV/div,AC

7pin:1V/div,DC

T

OUT1

IN1

Vref

3

5

+

-

+

R1 10k

Ω

10k

Ω

C1 0.22

μF

4.7k

Ω