PBL 385 71
+L
1
TO
2
TI
3
-L
4
-L
5
+C
6
Mute
7
GR
8
16
RE 2
15
RE 1
14
RI
13
-L
12
-L
11
M2
10
M1
9
MO
+L
1
TO
2
TI
3
-L
4
-L
5
+C
6
Mute
7
GR
8
16
15
14
13
12
11
10
9
RE2
RE1
RI
-L
-L
MI
MI
MO
16-pin BW DIP
16-pin BW SO
Figure 5. Pin configurations.
Pin Descriptions
Refer to figure 5.
Pin Name
1
2
+L
TO
Function
Output of the transmitter amplifier. Connected to the line through a polarity guard diode bridge.
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. impedance and the signal is used
to drive a side tone balancing network.
Input of transmitter amplifier. Input impedance 17 kohm
±
20 %.
Negative power terminal, connected to the line through a polarity guard diode bridge.
Positive power supply terminal for most of the circuitry inside the PBL 385 71 (about 1 mA current
consumption). The +C pin should be connected to a decoupling capacitor of 47
µF
to 150
µF.
Mute input. Maximum voltage (to mute) is 0.3 V, current sink requirement of external driver is 100
µA.
Input for the gain regulation control circuitry.
Output of the microphone amplifier.
3
4,12
5,13
6
7
8
9
10
11
14
15
16
TI
}
-L
+C
Mute
GR
MO
MI 1
MI 2
RI
RE 1
RE 2
}
}
Inputs of the microphone amplifier. Input impedance 1.7 kohm
±
20%.
Input of receiver amplifier. Input impedance is 38 kohm
±
20 %.
Receiver amplifier outputs. Output impedance approximately 3 ohms.
4
ERICSSON [ ERICSSON ]
