PBL 3881
1
2
22
21
20
19
18
17
16
15
14
13
12
3
24
23
22
21
20
19
18
17
16
15
14
13
1
2
4
5
3
4
6
5
7
5
6
25
24
23
22
21
20
19
6
8
7
7
8
8
9
9
9
10
11
10
11
10
11
12
28 PLCC
24 pin SO
22 DIP
Figure 7. Pin configuration.
Pin Descriptions
Refer to figure 7. ( 22-pin dual-in-line package, 24pin SO package and 28-pin PLCC package )
22-Pin 24-pin 28-Pin Symbol Description
22-Pin 24-pin 28-Pin Symbol Description
DIP
SO
PLCC
DIP
SO
PLCC
11
11
13
F4Out
Output of the first and input of
the second amplifiers in the
receiver channel.Sense point
for the internal reference
voltage.
1
24
1
- TxIn
+ TxIn
F1Out
F2In
Transmitter channel negative input.
Input impedance 3.16 kohm.
Transmitter channel positive input.
Input impedance 100 kohm.
Output of the first amplifier in the
transmitter channel.
Input of the second amplifier in the
transmit channel. Input impedanc
varies with gain of F2 from 20 kohm
at high gain to 89 kohm at low gain.
2
3
4
1
2
3
2
3
12
13
12
13
14
15
+ RxIn Receiver channel positive input.
Input impedance 100 kohm.
- RxIn Receiver channel negative
input. Input impedance
4
10 kohm.
14
15
14
15
16
17
CTR Control input for gain dynamics,
mute, and shut down.
5
6
4
5
5
6
TxOut Transmitter channel output. Min.
ac.load impedance 25 kohm.
TxDet Transmitter signal detector output.
Goes positive in reference to the
internal reference voltage,1.9 V,
V+
Supply for the speech-
switching circuitry. A shunt
regulator voltage approximately
3.2 V at 1.5 mA.
when a transmitt signal is present.
16
17
16
17
20
23
GND System ground (-line).
7
7
9
NDet
Background noise detector output.
Goes negative in reference voltage,
to the int. reference voltage 1.9V
when a noise of a longer duration
appears.
LS
Loudspeaker power amplifier
output.
18
20
21
19
19
21
22
20
24
26
27
25
RDC
RE
-C
A
Pins for loudspeaker amplifier
supply options. Described in
the text.
Positive supply for the loud-
speaker amplifier.
8
9
8
9
10 CMP Comparator input. External resist-
ance to this input should be 50
kohm. Summing point to the
22
23
28
BIn
Signal input for the loudspeaker
amplifier. Input impedance 30
kohm.
different detector outputs.
11 RxDet Receiver signal detector output.
Goes negative in reference to the
internal reference voltage, appro-
ximately 1.9 V, when signal is
6
7
8
18
19
21
22
NC
NC
NC
NC
NC
NC
18
present at RxIn.
10
10
12 RxOut Receiver channel output. Min.
ac.load impedance 25 kohm.
5
ERICSSON [ ERICSSON ]
