TEA7063 ST Microelectronics, Inc., TEA7063 Datasheet - Page 10

• Manufacturer Part Number: TEA7063
• Description: Speech Circuit With Power Management
• Manufacturer: ST Microelectronics, Inc.

Figure 8
TEA7063
5. MICROPROCESSOR INTERFACE
5.1 Microprocessor Supply (pin 19)
At ”off-hook” the first priority of the circuit is to
make some current available at the Microproces-
sor Supply (pin 19) to charge quickly the external
capacitor C2.
This charging current is I
T-charge of about 10ms is necessary, with C2 =
47/ F. to charge pin 19 at the specified value of
3.3V typical at I
T-charge =
6. CURRENT SOURCE FOR SPEAKERPHONE
6.1 Current Source (pin 12)
Most of the DC current available from the line is
delivered by the speech circuit at the output I
(pin 12) through an internal current generator.
Typical values of this current, l
are:
I
I
(ex: I
Figure 9
10/15
LS
LS
= (0.3 I
= (0.9 I
LINE
= 16mA then I
3.3V
0.6
LINE
LINE
LINE
)
-10mA) for I
I
LINE
C2
= 25mA:
LS
for I
typically
cpm
= 5mA
LINE
LINE
= 0.6 I
LS
< 16.5mA
> 16.5mA
with R9 = 100K,
LINE
source
V
creases linearly from 0.5mA min, at I
to1.5mA, at I
higher values of I
In general:
I
I
A zener of 3.9V typical is generally suggested to
I
I
The voltage level at pin 12 must be defined by an
external regulator (i.e.: zener) and, if necessary,
filtered with a capacitor (47 to 220 F).
In case V
pin 12, then the internal current source switches
off and its DC current is shunt to ground through
and internal complementary generator, thus
avoiding any negative effect on the AC and DC
impedances of the telephone set application.
mp
mp
LINE
LINE
mp
=
=
= 3.3V in normal operation and current in-
= 30mA then I
= 60mA then I
130Volt
11Volt
R9
R9
LINE
+ 0.3mA at I
LINE
+ 0.3mA at I
(at pin 16) approaches voltage at
LINE
= 25mA, remaining stable for
LS
LS
. (with R9 = 100K)
= 17mA
= 44mA).
L
L
> 6mA
> 25mA
LINE
= 6mA,