L6726

LINEAR INTEGRATED CIRCUIT

UNISONICTECHNOLOGIESCO.,LTD

4 of 13

www.unisonic.com.tw

QW-R108-015, C

FUNCTIONAL DIAGRAM

10

12

13

DC

7

9

85

11

3

2

15

16 6

14

4

17

18

AR

AT

AM

1

UTC L6726

1.Impedance to line and radio interference suppression.

2.Transmit gain and frequency response network.

3.Receive gain and frequency response network.

4.Side tone balance network.

5.DC-supply components.

AD

DTMF

input

DC output for external

CMOS device

5

2

4

1

3

Mute

(active low)

Telephone

Line

+LINE

-LINE

REC

MUTE

V4

DTMF

ARTIFICAIAL

LINE

C1

1μF

600Ω

V1

V2

=400Ω+400Ω

Fig. 1 Test setup without rectifier bridge

5H+5H

0 Ω when artificail line is used

C1= 1μF when artificial line is used

470μF when not used

V3

MIC

E=48.5V

UTC 6726

with external

component

see fig 3

+

+

+LINE

-LINE

REC

MUTE

V4

DTMF

C1

1μF

600Ω

V1

V2

Fig. 2 Test setup with rectifier bridge

5H+5H

E=50V

Uz=(15 ~16)V

MIC

V3

=400Ω+400Ω

UTC 6726

with external

component

see fig 3

+

+