TEA1064A/C1 Philips Semiconductors (Acquired by NXP), TEA1064A/C1 Datasheet - Page 7

• Manufacturer Part Number: TEA1064A/C1
• Description: TEA1064A; Low Voltage Versatile Telephone Transmission Circuit With Dialler Interface And Transmit Level Dynamic Limiting
• Manufacturer: Philips Semiconductors (Acquired by NXP)

Philips Semiconductors
The maximum AC output swing on the line at low line
currents is influenced by R16 (limited by current) and the
maximum output swing on the line at high line currents is
influenced by the DC voltage V
In both these situations, the internal dynamic limiter in the
sending channel prevents distortion when the microphone
input is overdriven. The maximum AC output swing on LN
is shown in Fig.5; practical values for R16 are from 200 to
600
at low line currents and the supply capabilities.
The SLPE pin is the ground reference for peripheral
circuits, therefore inputs MUTE, PD and DTMF are also
referenced to SLPE.
Active microphones can be supplied between V
V
inputs to the TEA1064A also can be powered from V
However V
DTMF signals to the TEA1064A because V
to ground.
If the line current l
converter shunts the excess current to SLPE via LN;
where I
normal operation.
March 1994
handbook, halfpage
EE
Low voltage versatile telephone transmission circuit
with dialler interface and transmit level dynamic limiting
l
Line current has very little influence
Fig.4
line
. Low-power circuits that provide only MUTE and/or PD
(mA)
I p
= 15 mA; R16 = 392 ; R15 = 0 ; valid for MUTE = 0 and 1.
and this influences both the maximum output swing
CC1
5
4
3
2
1
0
2
Minimum supply current for peripherals (I
as a function of the peripheral supply
voltage (V
CC1
1.3 mA, the value required by the IC for
cannot be used for circuits that provide
line
exceeds I
p
).
3
LN-SLPE
CC1
0.25 mA, the voltage
(limited by voltage).
4
CC1
MGR059
V p (V)
is referred
CC1
and
p
CC1
)
.
7
The DC line voltage on LN is:
in which
With R9 = 20 , this results in:
The preferred value for R9 is 20 . Changing R9
influences microphone gain, DTMF gain, the gain control
characteristics, sidetone, and the DC characteristics
(especially the low voltage characteristics).
In normal conditions, I
static behaviour is equivalent to a voltage regulator diode
with an internal resistance of R9. In the audio frequency
range the dynamic impedance is determined mainly by R1.
The equivalent impedance of the circuit in the audio
frequency range is shown in Fig.6.
The internal reference voltage V
by external resistor R
REG and SLPE. The supply voltage V
a function of R
reference voltage influences the output swing of both
sending and receiving amplifiers.
At line currents below 8 mA (typ.), the DC voltage dropped
across the circuit is adjusted to a lower level automatically
(approximately 1.8 V at 2 mA). This gives the possibility of
operating more telephone sets in parallel with DC line
voltages (excluding polarity guard) down to an absolute
minimum of 1.8 V. At line currents below 8 mA (typ.), the
circuit has limited sending and receiving levels.
V
V
V
between V
external resistor R
R9 = external resistor between SLPE and V
basic application).
V
V
R
V
R
LN
LN
ref
LN
LN
LN
VA(REG-SLPE)
VA(REG-SLPE)
= 3.3 V
= V
= V
= 3.57
= 4.17
= 4.57
LN-SLPE
ref
CC2
([I
VA(REG-SLPE)
0.25 V at l
0.3 V at l
0.35 V at l
0.25 V is the internal reference voltage
line
= 33 k
= 20 k
and SLPE; its value can be adjusted by
(I
VA
SLPE
VA(REG-SLPE)
I
SLPE
CC1
line
line
line
>> (I
in Fig.7. Changing the
= 15 mA,
R9)
0.25
= 15 mA
= 15 mA,
CC2-SLPE
CC1
connected between
10
Product specification
CC2-SLPE
0.25 mA) and the
3
TEA1064A
A]
can be increased
R9)
is shown as
EE
(20
in