PBL 388 14
-Txin 1
+Txin 2
F2out 3
Txout 4
TxDetin 5
TxDetout 6
Ref. 7
N Det
8
24 CTR
23 LSPin
-Txin 1
24 CTR
23 LSP in
22 V
A
21 VOL
20
LL
22 V
A
+Txin 2
21 VOL
20 LL
19
LSP
F2out 3
Txout 4
TxDetin 5
TxDetout 6
Ref.
N Det
7
8
9
18 GND
A
17 GND
16
V+
19 LSP
18
GND
A
17 GND
16
V+
CMP 9
RxDetout 10
RxDetin 11
Rxout 12
CMP
15 -Rxin
14 +Rxin
13 F5out
RxDetout 10
RxDetin 11
Rxout 12
15 -Rxin
14 +Rxin
13 F5out
24 pin DIP
24 pin SO
Figure 4. Pin configuration.
Pin Descriptions
Refer to figure 6. (24 pin DIP and 24 pin SO package)
Pin
1
2
3
4
5
6
Symbol
-Txin
+Txin
F2out
Txout
TxDetin
Description
Transmitter channel negative input.
Input impedance 3.16 kohm.
Transmitter channel positive input.
Input impedance 100 kohm.
Output of the second amplifier in the
transmitter channel.
Transmitter channel output. Min. ac
load impedance 10 kohm.
Input of the transmitter channel signal
detector. Input impedance 13 kohm.
Pin
11
12
13
14
15
16
Symbol
RxDetin
Rxout
F5out
+Rxin
-Rxin
V+
Description
Input of the receiver channel signal
detector. Input impedance 13 kohm.
Receiver channel output. Min. ac load
impedance 10 kohm.
Output of the second amplifier in the
receiver channel.
Receiver channel positive input. Input
impedance 140 kohm.
Receiver channel negative input. Input
impedance 20 kohm.
Supply of the speech switching circuitry.
A shunt regulator, voltage apprx. 3.3V at
1.0mA.
System ground.
Power amplifier ground. Can lie positive
relative to GND, otherways connected
externally to GND.
Loudspeaker power amplifier output.
Feedback loop input
Volume control input. By sourcing a
current of appx. 0-40
µA
into this pin the
gain can be reduced.
Positive supply for the loudspeaker
amplifier.
Loudspeaker amplifier signal input. Input
impedance 30 kohm.
Control input for gain dynamics
(25 or 50dB), mute and disable.
TxDetout Output of the transmitter channel signal
detector. Goes nagative referred to the
internal ref. voltage of appx. 2V when a
transmitter signal is present.
Ref.
NDet
Internal reference app. 2V.
17
18
GND
GND
A
7
8
9
10
Background noise detector output.
Goes positive referred to the internal ref.
voltage of app. 2V when a background
19
noise signal is present
20
CMP
Comparator input. External resistance
21
to this point should not be less than
50 kohm. Summing point to the different
detector outputs.
22
RxDetout Output of the receiver channel signal
detector. Goes positive referred to the
23
internal ref. voltage of appx. 2V when a
receiver signal is present
24
LSP
LL
VOL
V
A
LSPin
CTR
5
ERICSSON [ ERICSSON ]
