PBL 388 13
-Txin
1
24
CTR
-Txin
1
24
CTR
23
LSP in
22
R
E
21
R
DC
20
19
18
17
+L
VOL
LSP
-C
+Txin
2
F2out
3
Txout
4
TxDetin
5
TxDetout
6
N Det
7
CMP
8
RxDetout
9
RxDetin
10
Rxout
11
F5out
12
23 LSPin
22 R
E
21 R
DC
20
19
18
17
16
15
14
+L
VOL
LSP
-C
+Txin
2
F2out
3
Txout
4
TxDetin
5
TxDetout
6
N Det
7
CMP
8
GND
RxDetout
9
16
GND
15
V+
14
-Rxin
13
+Rxin
V+
RxDetin
10
-Rxin
Rxout
11
F5out
12
13 +Rxin
24 pin DIP
24 pin SO
Figure 6. 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
Symbol
Rxout
F5out
+Rxin
-Rxin
V+
Description
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 (- line ).
Loudspeaker power amplifier output.
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.
Power ampl. supply options. Pins - C,
RDC and RE are explained in the text.
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.
NDet
16
17
GND
-C
LS
VOL
7
8
CMP
18
Background noise detector output.
19
Goes positive referred to the internal ref.
voltage of app. 2V when a background
noise signal is present
20
Comparator input. External resistance
to this point should not be less than
50 kohm. Summing point to the different 21
22
detector outputs.
23
24
+L
RDC
RE
LSPin
CTR
9
RxDetout Output of the receiver channel signal
detector. Goes positive referred to the
internal ref. voltage of appx. 2V when a
receiver signal is present
RxDetin
Input of the receiver channel signal
detector. Input impedance 13 kohm.
10
5
ERICSSON [ ERICSSON ]
