KX-UT670RU - Panasonic Telephone Service Manual (repair manual). Page 17

17

The acoustic signal that entered MIC of SP-Phone is converted into the electrical signal in MIC,and
the signal flows as follows.
→ Analog Amplifier(IC1) → A/D convertor → Digital Gain Amp → Output(IP Line)
MC bias voltage is supplied from IC1 to MIC through R301 and R303

Receiving singnal that enters from IP line flows as follows.
→ Digital Gain Amp → D/A convertor → Analog Amplifier → Output → pin3,4 of IC301(D-class Amplifier)
→ pin5,8 of IC301
After that ,electrical signal is convered to acoustic signal in speaker of SP-Phone.

DG

DG

DG

DG

DG_SP

3.3V

C303

10u 6.3

LED5.0

L303

L304

SG

SG

C316 0.22u
C317 0.22u

C309

1u

10

C304
0.47u
C305
0.47u

R303 1k

R301

1k

R302

2.2k

R329

0

R304

NC

C307 100p

C306

100p

C315

NC

C314

NC

C302 1000p

C301

1000p

C312

1000p

L301

L302

SPK_shutdown

R326 NC

DL301

1

2

3

C308

10u

16

SPH_MICP

SPH_MICN

SPH_SPN

SPH_SPP

C334

100p

50

C344

100p

50

C346

NC

3.3V

D312

2

1

3

D314

D313

D321

D322

IC301

1 STBY

2 NC

3 IN+

4 IN-

5

OUT+

6

VDD

7

GND

8

OUT-

9

FIN

IC1

AD7

MIC1_A_BIAS

AC8

MIC1_AP

AB8

MIC1_AN

AC12

SPK1_AP

AB12

SPK1_AN

AE7

MIC1_B_BIAS

AD8

MIC1_BP

AE8

MIC1_BN

AE12

SPK1_BP

AD12

SPK1_BN

D326

2

1

3

MIC+

MIC-

SP-

SP+

C311

0.01u

C310

0.01u

C252

NC

R390 0

R391 0

R306

10k

R307

10k

MIC

SP