U4089B-PFN ATMEL [ATMEL Corporation], U4089B-PFN Datasheet - Page 5

• Manufacturer Part Number: U4089B-PFN
• Description: Monolithic Integrated Feature Phone Circuit
• Manufacturer: ATMEL [ATMEL Corporation]

DC Line Interface and
Supply-voltage
Generation
4518A–CORD–05/02
The DC line interface consists of an electronic inductance and an output stage which
charges the capacitor at V
L = R
In order to improve the supply during worst-case operating conditions, the PNP current
source (I
in parallel is unable to conduct current.
The U4089B-P contains a series regulator which provides a supply voltage V
at 2 mA suitable for a microprocessor.
Figure 4. DC Line Interface with Electronic Inductance and Generation of Regulated
Figure 5. Functional Blocks for Power Supply
V
V
L
L
SENSE
BOPT
10 F
R
R
LIDET
supply
Power
C
10
SENSE
and Unregulated Supply
DC
IND
) supplies an extra amount of current to the supply voltages when the NPN
C
IND
V
TXACL
LON
TXA
SENSE
IND
(R
DC
< 5 mA
I
30 k
R
BOPT
B
30
R
V
. The value of the equivalent inductance is given by:
OFFSA
COMP
OFFS
+
30
-
) / (R
DC
+ R
regulator
SAL, SA
Voltage
SACL
30
)
AFS
+
-
7 V
MUT REC, STBAL
3.3 V
MIC, DTMF
TX MUTE
AGA, RA
7V
RECATT
ES
V
CONTR
IMPED
V
U4089B-P
MP
B
3.3 V/
2 mA
MP
V
V
IMPSEL
of 3.3 V
B
MP
47 F
220 F
5