PBL 3726/18A
+L
TO
1
2
3
4
5
6
7
8
9
18 RE 2
17 RE 1
16 DR
15 RI
20
RE 2
+L
TO
1
2
19 RE 1
18 DR
17 RI
TI
TI
3
+C
+C
4
Mute
GR
5
16 -L
Mute
GR
14 -L
6
15 MI 2
14 MI 1
13 MO
12 DI
13 MI 2
12 MI 1
11 MO
10 DI
DCS
DCO
DCC
NC
7
DCS
DCO
DCC
8
9
10
11 NC
20-pin SO
18-pin DIP
Figure 5. Pin configuration.
Pin Descriptions
Refer to figure 5.
DIP SO
Name
Function
1
1
+L
Output of the DC-regulator and transmit amplifier. This pin is connected to the line through a polarity
guard diode bridge.
2
2
TO
Output of the transmit amplifier. This pin is connected through a resistor of 47 to 100 ohm to -L,
which 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
3
4
TI
Input of transmit amplifier. Input impedance 17 kohm ± 20 %.
+C
This pin is the positive power supply terminal for most of the circuitry inside the PBL 3726/18A
(about
capacitor of 47 µF to
1 mA current consumption). The +C pin shall be connected to a decoupling
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
This pin is control input for the gain regulation circuitry.
This pin is the sense input to the DC-supply.
7
7
DCS
DCO
DCC
DI
8
8
This pin is the output from the DC-supply.
9
9
This pin is the control output from the DC-supply.
10
11
12
13
14
15
16
17
18
12
13
14
15
16
17
18
19
20
10
11
This pin is the input for the DTMF-signal. Input impedance is 25 kohm ± 20 %.
Output of the microphone amplifier or DTMF-amplifier.
Inputs to the microphone amplifier. Input impedance 1.7 kohm ± 20 %.
MO
MI 1
}
MI 2
-L
The negative power terminal, connected to the line through a polarity guard diode bridge.
Input of receiver amplifier. Input impedance is approximately 38 kohm ± 20 %.
This pin is the control input for the receiver amplifier driving capability.
Receiver amplifier outputs. Output impedance is approximately 3 ohm.
RI
DR
RE 1
RE 2
}
NC
NC
4
ERICSSON [ ERICSSON ]
