AN5273 データシートの表示（PDF） - Panasonic Corporation

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AN5273

4.0 W ×2 (18 V, 8 Ω) Power Amplifier with Mute Function and Volume Control

Panasonic Corporation 

ICs for Audio Common Use

AN5273

s Technical Information (continued)

2.Application Note

1) Voltage gain

The voltage gain of the AN5273 can be varied by changing the resistor R2 as shown below :

GVI

GV input= 4 dB Pin8

which is fixed in 11

internal circuit.

Pin7,12

R1

R1 is always fixed at 20 kΩ.

R2 is variable.

GVO = 20 log (R1/R2)

Typical values are : R1 = 20 kΩ, R2 = 1 kΩ

CNF = 10 µF

R2

GVO = 20 log (20 k/1 k)

= 26 dB

GVTOTAL = GVI + GVO

= 4 dB + 26 dB

= 30 dB

2) DC volume control

The DC volume control range is 0 V to 5 V. This range is used in order to be easily controlled by micro-computer

using PWM output. The recommended circuit and volume attenuation characteristic are shown below :

AN5273

300 Ω 3

Volume

control

R4

18 kΩ

C4

2.2 µF

R5

12 kΩ

Microcomputer IC

PWM

output

Volume

attenuation

Fig. Volume control interface circuit for AN5273

0 0.6 Volume at Pin3 5 (V)

Fig. Volume characteristic of AN5273

3) Mute control

Mute is ON when 5 V is applied to Pin1. Then Q1 would turn ON and able to drive other part of the circuits. The

external RC components provide a time constant for switching ON and OFF.

Mute ON 5 V R

0V

OFF

100 kΩ

ZMUTE

1

The purpose of the Mute is to

Q1 attenuate the AC signal before

C

1.0 µF

20 kΩ

it goes to the output.

0V

Threshold voltage at Pin1 :

1.8 V 2.1 V

Mute OFF

Mute ON

5V

5

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