3544

LINEAR INTEGRATED CIRCUIT

UNISONICTECHNOLOGIESCO.,LTD

7 of 10

www.unisonic.com.tw

QW-R107-040,C

APPLICATION EXAMPLE

8

7

65

12

34

BIAS

90K

90K

6dB

6dB

TSD

MUTE

+

+

OUT1

MUTE

IN1

GND

Vcc

OUT2

BIAS

IN2

H:Active

L:Mute

100k

1μ

1μ

1μ

47μ

+

+

+

+

330μ

Vcc

C3

C5

C6

C2

R2

C1

C7

330μ

EXPLANATION OF EXTERNAL COMPONENTS

(1)Input coupling capacitor (C3 and C5)

First determined by the low-band cut-off frequency. Because the input impedance is 180kΩ for this IC, it can be

determined by this formula

C3(C5)=1/(2π×180kΩ×f)

But make sure taking the fluctuations, ambient temperature, etc into consideration. A multi-layered ceramic

capacitor is recommended.

(2)BIAS capacitor(C6)

47μF when Vcc=5V, and 33μF when Vcc=3V. Before changing these values take the sufficient considerations.It is

because the electrical characteristics will be adversely affected and popping noise may occur if the capacitance is

lowered too much.

(3)MUTE pin for anti-pop measures (R2 and C2)

An impedance of 190kΩ must be possessed with respect to GND, so the MUTE mode may become unable to be

released if R2 is increased too much.

(4)Output coupling capacitor(C1 and C7)

inserted ,assuming that for output protection or current limiting), it can be calculated by this formula

(5)Input gain adjustment resistor(R3 and R4)

External resistors R3 and R4 can perform input gain adjustment .The desired gain can be calculated by this

formula

Gv=6+20log(90kΩ/(90kΩ+R3))[dB]