pbl385701sot ETC-unknow, pbl385701sot Datasheet - Page 11

• Manufacturer Part Number: pbl385701sot
• Description: Universal Speech Circuit
• Manufacturer: ETC-unknow

and line current compensated DC supplies
DC1 and DC2. DC1 is a voltage supply for
supplying diallers, can also be used for
memory back up because it does not leak
any current back into the circuit. Typical
voltage 2.4V down to line voltage of 4.1V,
in case the line voltage is lower than 4.1V
calculate ; actual line voltage minus 1.9V.
In order to prevent noise entering the line,
a series resistor and a reservoir capaciotor
is recommended in series at this output.The
output current is given to be 2 mA in the
specification. In case this would not be
Figure 17. DC-supplies
Figure 18. Typical DTMF tone dialling telephone. 18-pin DIP package. * marked components for gain regulation.
The circuit has further two temperature
+
DIALLER
V
CMOS
R
R
I
1
4
7
*
L
exh.
Line
Feed
V
5
2
8
0
L
a. Supply arrangement for a handsfree system power amplifier. For ex. PBL 38811---14
b. Supply arrangement for a call monitor cicuit.
DTMF 12
3
6
9
#
MUTE 9
+Line
-Line
VDD
GND
33k
3.3n
680p
Hook
switch
1-10M
V
PA
a.
MIC.
220
220
+
1 F
1 F
V
Mon.
47 F
b.
100
+
10
12
13
8
+
DC-supply
9
+
100
47 F
V
+
7
enough the current capability can be
increased by connecting the outputs of
DC1 and DC2 in parallel. The driving capa-
city will increase almost to the double but
the voltage drop across the necessary
series resistor will go upp thus limiting the
useful current.
both of these supplies is set by DC2. DC2
is a high precision, reference quality supply
that can be used to supply microphones,
opto couplers etc. The internally set voltage
can be adjusted with external resitors when
needed (R
R3
+C
C1
Voltage
adjust
The voltage level that is common for
AM
4
AD
2
R6
5
PBL 38 570
*
*
DC1
ƒ
6
18k
22k
T
+
and R
-
11
3
100n
75
AT
DC2
Lim
+
V
3
2
1
).
100n
910
PBL 385 70
1
560
Ref.
1.2V
11k
6.2k
+
-
11k
15
47n
10
15k
15k
AR
14
16
14
advantage that it does not influence the
circuits DC characteristics even at high
current drain. The supply has a floating
ground reference in the plus line in order to
minimize RFI problems and is used to
supply the power amplifier of a handsfree
telephone ( PBL3881, 38811---14 ). These
circuits have a current controlled charging
of the supply capacitor and the control
signal is taken across the resistor R6. In
case a monitor amplifier is required where
the ground reference is hardly necessary,
it can be supplied from V PA or like in alt. b
in fig. 17.
62k
The fourth DC-supply V PA has an
8
9
7
+
18
17
4
0-470
100
10n
R
R
+
910
DC1
47 F
DC2
1-10M
Rec.
+
15n
Hook switch
4.7-47
0-470
F
PBL 385 70
15V
+
4.7-47
10
V
V
F
DC1
DC2
Telephone line
11