PBL 385 71
+L
TO
TI
1
2
3
4
5
6
7
8
RE 2
RE 1
16
15
14
13
12
11
10
9
1
2
16
15
+L
RE2
RE1
RI
TO
RI
-L
-L
3
4
5
6
14
13
TI
-L
-L
-L
-L
12
11
10
9
-L
-L
+C
MI
MI
MO
+C
M2
M1
MO
7
8
Mute
GR
Mute
GR
16-pin BW DIP
16-pin BW SO
Figure 5. Pin configurations.
Pin Descriptions
Refer to figure 5.
Pin Name
Function
1
2
+L
Output of the transmitter amplifier. Connected to the line through a polarity guard diode bridge.
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. impedance and the signal is used
to drive a side tone balancing network.
3
TI
Input of transmitter amplifier. Input impedance 17 kohm ± 20 %.
4,12
5,13
- L
Negative power terminal, connected to the line through a polarity guard diode bridge.
}
6
+C
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.
7
8
Mute
GR
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.
9
MO
Output of the microphone amplifier.
10
11
14
15
16
MI 1
MI 2
RI
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.
}
}
RE 1
RE 2
4
ERICSSON [ ERICSSON ]
