PBL 3786
Tx
Out
27
R
E
28
-C
Tx
in
2
Tx
Out
Tx
Det
N
Det
CMP
Rx
Det
Rx
Out
3
4
5
6
7
8
21
20
19
18
17
16
15
14
13
12
R
E
+L
R
DC
LS
2
R
VIN
GND
LS1
PWM
µ
PC
HF
µ
PS
LF
µ
PA
NC
Tx
Det
NC
NC
N
Det
5
6
7
8
9
26
+L
B
in
1
Tx
in
2
NC
22
-C
4
3
1
B
in
25
R
DC
24
NC
23
LS
2
22
NC
21
R
VIN
20
GND
19
LS
CMP
10
Rx
Det
11
1
Rx
in
9
CTR
10
V+
11
22-pin DIP
PWM
µ
PC
18
Rx
Out
12
Rx
in
13
CTR
14
V+
15
LF
µ
PA
16
HF
µ
PS
17
28 PLCC
Figure 9. Pin configurations.
Pin Descriptions
Refer to figure 9. (22-pin dual-in-line package and 28-pin PLCC package)
22-Pin DIL 28-Pin PLCC Symbol
Description
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
21
22
20
1
2
4
6
9
10
11
12
13
14
15
16
17
18
19
20
21
23
25
27
28
26
3,5,7,8
22,24
B
In
Tx
In
Tx
Out
Tx
Det
N
Det
CMP
Rx
Det
Rx
Out
Rx
In
CTR
V
+
LFµPA
HFµPS
PWMµPC
LS1
GND
R
VIn
LS2
R
DC
R
E
-C
+L
NC
NC
Signal input loudspeaker amplifier. Input impedance 30 kohm.
Transmit channel input. Input impedance 3.2 kohm.
Transmit channel output. Minimum load impedance 25 kohm.
Transmit channel detector output. Goes positive in reference to the internal reference voltage
when signal is present at Tx
In
, approximately 1.9 V.
Background noise detector output. Goes negative when a noise of longer duration appears at
Tx
In
.
Comparator input. External resistance to this input should be 50 kohm. Summing point to the
different detector outputs.
Receive channel detector output. Goes negative in reference to the internal reference voltage
when signal is present at Rx
In
, approximately 1.9 V.
Receive channel output. Minimum load impedance 25 kohm.
Receive channel input. Input impedance 10 kohm.
Control input for gain dynamics and mute.
Supply for the speech-switching circuitry. A shunt regulator sets the voltage to approx. 3.2 V
at 1mA.
Low-frequency tone ringer oscillator set by a capacitor (shift frequency),
µP-mode,
see text.
High-frequency tone ringer oscillator set by a capacitor.
µP-mode,
see text.
Tone ringer volume control.
µP-mode,
see text.
Loudspeaker ground switch for tone ringer.
Ground for the whole system (-line).
Supply for the tone ringer and it’s output stage.
Common output for loudspeaker and tone ringer power amplifiers.
Pins for the loudspeaker amplifier supply options
described in text.
Reservoir capacitor negative supply for the loudspeaker amplifier.
Positive supply for the loudspeaker amplifier.
6
ERICSSON [ ERICSSON ]
