PBL 385 73
+L
TO
1
2
3
4
5
6
7
14 RE 2
13 RE 1
14
+L
TO
1
2
3
4
5
6
7
RE 2
13 RE 1
TI
12
11
10
9
RI
-L
TI
12
RI
+C
+C
7
11
-L
Mute
GR
MI 2
MI 1
MO
Mute
GR
6
10
MI 2
MI 1
MO
9
8
8
DCO
DCO
14-pin DIP
14-pin SO
Figure 5. Pin configurations.
Pin Descriptions:
Refer to figure 5.
Pin Name
Function
1
2
+L
Output of the DC-regulator and transmit amplifier. This pin is connected to the line through a polarity
guard diode bridge.
TO
Output of the transmit amplifier. This pin is 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
4
TI
Input of transmit amplifier. Input impedance 17 kohm ± 20 %.
+C
Positive power supply terminal for most of the circuitry inside the PBL 385 73 ( current consumption
about 1 mA). The +C pin shall be connected to a decoupling capacitor of 47 µF to 150 µF.
5
6
Mute
GR
Maximum voltage (to mute) is 0.3 V, current sink requirement of external driver is 100 µA.
Input of the gain regulation with line length.
7
DCO
Output of the auxiliary DC-supply.
8
MO
MI 1
MI 2
-L
Output of the microphone amplifier or DTMF-amplifier.
9
Microphone amplifier Inputs. Input impedance 1.7 kohm ± 20 %.
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10
11
12
13
14
The negative power terminal, connected to the line through a polarity guard diode bridge.
RI
Input of receiver amplifier. Input impedance 38 kohm ± 20 %.
RE 1
RE 2
Receiver amplifier outputs. Output impedance is approximately 3 ohm.
4
ERICSSON [ ERICSSON ]
