NJU72011

– 9 –

APPLICATION NOTE

The NJU72011 is an audio line amplifier that eliminates the need for external dc-blocking output capacitors.

The NJU72011 has built-in pop suppression circuitry to eliminate disturbing pop noise during power-on,

power-off and mute-control.

1. Operating Principle

The NJU72011 has the built-in non-inverted input operational amplifiers, voltage inverter, and pop noise

suppression circuitry (Fig.1).

The voltage inverter for NJU72011 eliminates the need for external dc-blocking output capacitors. The pop

suppression circuitry for NJU72011 eliminates the pop noise during power-on, power-off and mute-control.

Fig.1 The NJU72011 functional block diagram

1.1 External parts

frequency determined in [fc=1/(2

Mute-Tr

Mute-Tr

1uF

+

10uF

1uF 1kΩ

820pF

Charge

Pump

2

Bias

INL

OUTL

V+

CP

CN

INR

OUTR

GND

MUTE

1uF

1kΩ

820pF

10uF

4.7uF

22kΩ

3

4

5

1

9

8

7

6

10

V-

Pop Noise

Suppression

+

R1

C2

C3

C11

C4

C6

C7

R2

C9

R3

C8