TEA1067/C2 Philips Semiconductors (Acquired by NXP), TEA1067/C2 Datasheet - Page 5

• Manufacturer Part Number: TEA1067/C2
• Description: TEA1067; Low Voltage Versatile Telephone Transmission Circuit With Dialler Interface;; Package: SOT102-1 (DIP18), SOT163 (SO20)
• Manufacturer: Philips Semiconductors (Acquired by NXP)

Philips Semiconductors
FUNCTIONAL DESCRIPTION
Supply: V
Power for the TEA1067 and its peripheral circuits is usually
obtained from the telephone line. The IC develops its own
supply at V
voltage V
e.g. dialling and control circuits.
Decoupling of the supply voltage is performed by a
capacitor between V
regulator is decoupled by a capacitor between REG and
V
The DC current drawn by the device will vary in
accordance with varying values of the exchange voltage
(V
resistance of the telephone line (R
The TEA1067 has an internal current stabilizer working at
a level determined by a 3.6 k resistor connected
between STAB and V
(I
supply current (I
peripheral circuitry connected to V
current is shunted to V
The regulated voltage on the line terminal (V
calculated as:
V
V
Where V
compensated reference voltage of 3.6 V and R9 is an
external resistor connected between SLPE and V
June 1990
line
EE
LN
LN
exch
Low voltage versatile telephone
transmission circuit with dialler interface
.
) is more than 0.5 mA greater than the sum of the IC
= V
= V
), the feeding bridge resistance (R
ref
ref
ref
CC
CC
CC
is an internally generated temperature
I
[(I
may also be used to supply external circuits
, LN, SLPE, REG and STAB
SLPE
and regulates its voltage drop. The supply
line
CC
) and the current drawn by the
I
R9; or
CC
CC
EE
EE
and V
(see Fig.7). When the line current
0.5
via LN.
EE
10
while the internal voltage
3
CC
line
A)
).
(I
p
) the excess
exch
I
p
]
), and the DC
LN
R9
) can be
EE
.
5
In normal use the value of R9 would be 20 . Changing the
value of R9 will also affect microphone gain, DTMF gain,
gain control characteristics, side-tone level and maximum
output swing on LN, and the DC characteristics (especially
at the lower voltages).
Under normal conditions, when I
the static behaviour of the circuit is that of a 3.6 V regulator
diode with an internal resistance equal to that of R9. In the
audio frequency range the dynamic impedance is largely
determined by R1. Fig.4 shows the equivalent impedance
of the circuit.
At line currents below 9 mA the internal reference voltage
is automatically adjusted to a lower value (typically 1.6 V
at 1 mA). This means that the operation of more sets in
parallel is possible with DC line voltages (excluding the
polarity guard) down to an absolute minimum voltage of
1.6 V. With line currents below 9 mA the circuit has limited
sending and receiving levels. The internal reference
voltage can be adjusted by means of an external resistor
(R
decrease the internal reference voltage, connected
between REG and SLPE it will increase the internal
reference voltage.
Current (I
depends on the external components used. Fig.10 shows
this current for V
receiving amplifier is driven the available current is further
reduced. Current availability can be increased by
connecting the supply IC (TEA1081) in parallel with R1, as
shown in Fig.17 (c), or by increasing the DC line voltage by
means of an external resistor (R
REG and SLPE.
VA
). This resistor connected between LN and REG will
p
) available from V
CC
2.2 V. If MUTE is LOW when the
CC
for peripheral circuits
SLPE
VA
) connected between
Product specification
>> I
CC
TEA1067
0.5 mA I
p
,