3544 Ver la hoja de datos (PDF) - Unisonic Technologies

Número de pieza

componentes Descripción

Fabricante

3544

HEADPHONE AMPLIFIER FOR CD-ROMS

Unisonic Technologies 

3544

„ APPLICATION EXAMPLE

LINEAR INTEGRATED CIRCUIT

Vcc

+

330μ+ C1

Vcc

8

C6+ 47μ

OUT2

7

BIAS

6

1μ

C3

IN2

5

TSD

BIAS

90K

6dB

+

+

6dB

90K

MUTE

VMUTE

H:Active

L:Mute

C7

+

330μ

1

OUT1

R2

2

MUTE

100k

C2 1μ

3

IN1

4

GND

1μ

C5

VIN2

VIN1

„ 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)

Also determined by the low-band cutoff frequency. Like the output load resistance value RL (a resistor Rx will be

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

C1(C7)=1/(2π×(RL+Rx) ×f)

(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]

UNISONIC TECHNOLOGIES CO., LTD

www.unisonic.com.tw

7 of 10

QW-R107-040,C

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