NJU72010 查看數據表（PDF） - Japan Radio Corporation

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NJU72010

2Vrms Ground Referenced Stereo Line Amplifier with LPF

Japan Radio Corporation  

NJU72010

! APPLICATION NOTE

The NJU72010 is an audio line amplifier that eliminates the need for external dc-blocking output capacitors.

The NJU72010 has built-in pop suppression circuitry to eliminate disturbing pop noise during power-on,

power-off and mute-control.

1. Operating Principle

The NJU72010 has the built-in non-inverted input operational amplifiers, voltage inverter, and pop noise

suppression circuitry (Fig.1).

The voltage inverter for the NJU72010 eliminates the need for external dc-blocking output capacitors. The

pop suppression circuitry for the NJU72010 eliminates the pop noise during power-on, power-off and

mute-control.

1uF 1kΩ R1

INL

1

C2 820pF C3

INR 10

C9

1kΩ R31uF

820pF C8

V+

10uF

+

C11

2 OUTL

Mute-Tr

Mute-Tr

OUTR 9

3 V+

Pop Noise

Suppression

GND 8

4 CP

Bias

1uF

C4

Charge

Pump

5 CN

MUTE 7

C7

22kΩ

4.7uF R2

V- 6

C6 10uF

+

Fig.1 The NJU72010 functional block diagram

1.1 External parts

1.1.1 Input coupling capacitors Ci (C2, C8)

The input coupling capacitor (Ci) and the total of the external resistance (R1, R3) and the input

resistance (Rin=218kΩ typ.) for the non-inverted terminal form a high-pass filter with the corner

frequency determined in [fc=1/(2π x (R1+218kΩ) x Ci)). It is necessary to adjust 1uF or more.

–9–

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