LA4919N

No.A0323-5/6

Test Circuit

External Components

〈Amplifier Block〉

C4 :

Ripple filter capacitor. We recommend a value of 47

µF.

C5 :

Sets the amplifier turn-on delay time. We recommend a value of 22

µF. (The turn-on delay time for

this value will be about 0.7 seconds.) While the speed with which the amplifier turns on can be

increased by reducing the value of this capacitor, this can result in impulse noise. We recommend

using a value of over 10

µF.

C6 and C8 :

Input capacitors. We recommend a value of 22

µF. Note that if modified, 3.3µF or lower values

should be used due to the relationship with impulse noise.

C7 :

Input reference amplifier capacitor. The same value as that for C6 and C8 must be used.

C9 and C10 :

Oscillation prevention capacitors. We recommend using polyester film capacitors with excellent

thermal characteristics. These are used together with R1, R2, R3, and R4.

C14 and C15

C11 :

Switching regulator oscillation prevention capacitor. We recommend a value of 1000pF.

C12 :

Power supply capacitor

C13 :

Switching regulator output smoothing capacitor. The LA4919N adopts a self-excited switching

regulator technique. Since this capacitor influences the self excitation stability characteristics and

the regulator efficiency, we recommend using a capacitor with a low equivalent series resistance

and excellent thermal characteristics. For the same reason, resistor R5 (2.2

Ω) is used together with

this capacitor.

C20 :

Pre-VCC power supply capacitor. This capacitor is not required when used connected to VCC.

1

28

2

27

3

26

4

25

5

24

6

23

7

22

8

21

9

20

10

19

11

18

12

17

13

16

14

15

HP IN1

HP IN2

HP D.C

HP Standby

AMP Standby

D.C

DDL

ON TIME

IN2

IN1

POWER GND

PRE GND

PRE VCC

IN VREF

HP OUT2

HP OUT1

POWER GND

OUT2-

OUT2+

SW GND

SWB

SWE

SW OUT

OUT1+

OUT1-

VCC

+B

+B

0.1

µF

+

+

+

+

++

+

+

+

+

R7 10

Ω

+

+

+

R5

2.2k

Ω

*C10 0.1

µF

*C9 0.1

µF

*DDL OUT

C12

1000

µF/25V

C13

2.2

µF/25V

C16

0.047

µF

C17

0.047

µF

C19 100

µF/10V

C18 100

µF/10V

Headphones

C11 1000pF

R2 2.2

Ω

*C14 0.1

µF

L1 200

µH

D1 Flywhool Di

R3 2.2

Ω

Tr1

Switching transistor

IC=2.5V

fT=30 to 50MHz

Components used during testing

- Tr1 : 2SD1667 (S rank)

- SANYO Electric Co., Ltd.

- D1 : SB10-05A2

- SANYO Electric Co., Ltd.

- L1 : A671HN-221L

- TOKO, Inc.

-C13 : OS capacitor

- SANYO Electric Co., Ltd.

R1 2.2

Ω

*C15 0.1

µF

R4 2.2

Ω

R6 10

Ω

C1

1

µF/10V

C3

47

µF/25V

C4

47

µF/25V

C5

22

µF/6.3V

C7

22

µF/6.3V

C20

10

µF/25V

C2

1

µF/10V

C6

2.2

µF/6.3V

C8

2.2

µF/6.3V

10k

Ω

*When measuring

DDL OUT, apply 5V

and measure through

a 10k

Ω resistor.

* : When used shorted to VCC (pin 19),

it is not necessary to add a capacitor

at pin 11.

* : Polyester film capacitor