tea1065t NXP Semiconductors, tea1065t Datasheet - Page 6

• Manufacturer Part Number: tea1065t
• Description: Versatile Telephone Transmission Circuit With Dialler Interface
• Manufacturer: NXP Semiconductors

Philips Semiconductors
The DC current flowing into the set is determined by the
exchange supply voltage (V
subscriber line (R
set (see Fig.4).
If the line current exceeds I
circuit itself (I
the peripheral circuits connected to V
regulator will divert the excess current via LN.
V
where: V
compensated reference voltage of 4.18 V and R9 is an
external resistor connected between SLPE and V
The preferred value of R9 is 20 . Changing R9 will
influence the microphone gain, gain control
characteristics, sidetone and the maximum output swing
on LN. In this instance, the voltage on the line (excluding
the diode rectifier bridge; see Fig.4) is:
V
where: V
source terminal of the external line current control
transistor and I
(I
March 1994
handbook, full pagewidth
DOC
LN
line
Versatile telephone transmission circuit with
dialler interface
= V
= V
= 0 in the voltage regulator mode and increases with
ref
LN
ref
GS
V
ref
is an internally generated temperature
is the voltage drop between the gate and
I
CC
SLPE
V
GS
DOC
(I
line
line
1.14 mA), plus the current I
R16
is the current sunk by pin DOC
R9 =
) and the DC voltage on the subscriber
I
CC
V exch
R exch
I
DOC
CC
0.3
exch
), the DC resistance of the
0.3 mA, required by the
R line
10
I DOC
3
V line
CC
TEA1065
I
then the voltage
p
R16
)
I line
p
R9
Fig.4 Supply arrangement.
required by
DC
AC
22
12
DOC
REG
C3
EE
.
9
STAB
R5
0.5 mA
I SLPE
6
I
Under normal conditions I
for the voltage regulator mode (I
behaviour of the circuit is equal to a 4.18 V voltage
regulator diode with an internal resistance of R9 in series
with the V
transistor. For the current regulator mode (I
static behaviour of the circuit is equal to a 4.18 V voltage
regulator diode with an internal resistance of R9 in series
with the V
and also in series with a DC voltage source R16
current I
In the audio frequency range the dynamic impedance
between LN and V
internal reference voltage V
of an external resistor R
between LN and REG, will decrease the internal reference
voltage. When R
the internal reference voltage will increase.
The maximum allowed line current is given in Figs 5 and 6,
where the current is shown as a function of the required
reference voltage, ambient temperature and applied
package.
line
I
LN
1
SLPE
DOC
24
R9
in the current regulator mode).
R1
(the preferred value of R16 is 1 M at this value the
DOC
GSon
GSon
V EE
16
0.3 mA
21
V CC
I CC
is negligible compared to I
of the external line current control transistor
of the external line current control
VA
EE
is connected between REG and SLPE
C1
is equal to R1 (see Fig.8). The
VA
SLPE
. This resistor, connected
MBA550
ref
peripheral
circuits
can be adjusted by means
>> I
line
I p
CC
Product specification
I
knee
line
0.3 mA
TEA1065
), the static
).
line
I
knee
I
p
and
), the