tea1098auh NXP Semiconductors, tea1098auh Datasheet - Page 7

• Manufacturer Part Number: tea1098auh
• Description: Speech And Handsfree Ic
• Manufacturer: NXP Semiconductors

Philips Semiconductors
FUNCTIONAL DESCRIPTION
All data given in this chapter are typical values, except
when otherwise specified.
Supplies
L
REG
The supply for the TEA1098A and its peripherals is
obtained from the line. The IC generates a stabilized
reference voltage (V
This reference voltage is equal to 3.7 V for line currents
lower than 18 mA. It than increases linearly with the line
current and reaches the value of 6.1 V for line currents
higher than 45 mA. For line currents below 9 mA, the
internal reference voltage generating V
adjusted to a lower value. This is the so-called low voltage
area and the TEA1098A has limited performances in this
area (see Section “Low voltage behaviour”). This
reference voltage is temperature compensated.
The voltage between pins SLPE and REG is used by the
internal regulator to generate the stabilized reference
2000 Aug 18
handbook, full pagewidth
INE INTERFACE AND INTERNAL SUPPLY
Speech and handsfree IC
AND
V
BB
GND
REG
)
LN
ref
) between pins SLPE and GND.
C REG
4.7 F
SLPE
(
TP1
TN1
PINS
R3
R2
ref
is automatically
LN, SLPE,
preamp
Fig.3 Line interface principle.
from
R1
J1
R SLPE
20
D1
7
J2
voltage and is decoupled by means of a capacitor between
pins LN and REG.
This capacitor converted into an equivalent inductance
realizes the set impedance conversion from its DC value
(R
The IC regulates the line voltage at pin LN and can be
calculated as follows:
where:
I
I
I
The preferred value for R
will affect more than the DC characteristics; it also
influences the transmit gains to the line, the gain control
characteristic, the sidetone level and the maximum output
swing on the line.
V
I
line
x
SLPE
SLPE
LN
= current consumed on pin LN (approximately a few A)
SLPE
E1
= line current
=
= current flowing through the R
) to its AC value (done by an external impedance).
=
GND
V
ref
I
TR1
line
+
–
R
I
SLPE
TN2
x
TR2
I
SLPE
SLPE
is 20 . Changing this value
MGM298
E2
GND
SLPE
Product specification
D1
TEA1098A
V BB
resistor