4

PBL 385 41

Figure 5. Pin configuration.

18-pin DIP

20-pin SO

Pin Descriptions

Refer to figure 5.

DIP

SO

Name

Function

1

1

+L

Output of the DC-regulator and transmitter amplifier, connected to the line through a polarity

guard diode bridge.

2

2

TO

Output of the transmitter amplifier, connected through a resistor of 47 to 100 ohm to -L,

sets the DC-resistance of the circuit. The output has a low AC output impedance and the

signal is used to drive a side tone balancing network.

3

3

TI

Input of the transmitter amplifier. Input impedance 17 kohm

± 20 %.

4

4

+C

Positive power supply terminal for most of the circuitry inside the PBL 385 41 (about 1 mA current

consumption). The +C pin must be connected to a decoupling capacitor of 47

µF to 150 µF.

5

5

Mute

When low, speech circuit is muted and the DTMF input is enabled. Maximum voltage (at mute) is

0.3 V, current sink requirement of external driver is 50

µA.

6

6

GR

Control input for the gain regulation function.

7

7

DCS 1

Control input to the DC1-supply. A resistor to -line sets the maximum current load of the supply.

8

8

DCO 2

Output of the DC2-supply.

9

9

DCO 1

Output of the DC1-supply.

10

12

DI

Input for the DTMF-signal. Input impedance 25 kohm

± 20 %.

11

13

MO

Output of the microphone amplifier or DTMF-amplifier.

12

14

MI 1

Inputs to the microphone amplifier. Input impedance 1.7 kohm

± 20 %.

13

15

MI 2

14

16

-L

The negative power terminal, connected to the line through a polarity guard diode bridge.

15

17

RI

Input of receiver amplifier. Input impedance 38 kohm

± 20 %.

16

18

DR

Control input for the receiver amplifier driving capability.

17

19

RE 1

Receiver amplifier outputs. Output impedance is approximately 3 ohm.

18

20

RE 2

10

Not connected

11

Not connected

+L

TO

TI

+C

Mute

GR

DR

RI

-L

MI 2

MI 1

MO

1

2

3

4

5

6

7

8

16

15

14

13

12

11

DI

9

10

RE 2

RE 1

18

17

1

2

3

4

5

6

7

8

19

18

17

16

15

14

13

+L

TO

TI

+C

Mute

GR

RE 2

RE 1

DR

RI

-L

MI 2

MI 1

MO

9

12

10

11

NC

DI

NC

4

5

17

16

20

}

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