
November 1994
8
Philips Semiconductors
Product Specification
Speech and listening-in IC
TEA1096; TEA1096A
FUNCTIONAL DESCRIPTION
Remark
: all data given in this chapter are typical values
except when otherwise specified.
Supply pins SLPE, LN, V
EE
, V
BB
, V
DD
, REG and PD
The supply for the TEA1096/TEA1096A and its
peripherals is obtained from the telephone line. The
circuits regulate the line voltage and generate their own
supply voltages V
DD
and V
BB
to power the transmission
part and the loudspeaker amplifier respectively.
As can be seen from Fig.5, the line current (I
line
) is split
between the sending output stage (I
ln
), the circuitry
connected to SLPE (I
sl
), the transmission circuit (I
DD
), the
peripheral circuits (I
p
) and the current switch (I
SUP
). It can
be shown that:
I
SUP
= I
line
(I
ln
+ I
sl
+ I
DD
+ I
P
)
With nominal conditions where:
I
ln
= 5 mA, I
sl
= 0.3 mA and I
DD
= 2.4 mA
it therefore follows that I
SUP
≈
I
line
7.7 mA
I
P
.
The remaining current I
SUP
is available for the listening-in
part. The current consumption I
BB0
of the listening-in
circuitry is 2.5 mA. To power the loudspeaker, the line
current has to be more than 10 mA.
The voltage at SLPE is stabilized at 4.45 V nominal. The
DC line voltage is regulated at:
V
LN
= V
SLPE
+ R
SLPE
×
(I
line
I
ln
).
The supply voltage for the transmission part and
peripheral circuits (V
DD
) is generated from V
SLPE
and is
equal to V
DD
= V
SLPE
R
DD
×
(I
DD
+ I
p
).
V
BB
supplies the listening-in circuitry and is stabilized at
3.6 V nominal.
A resistor connected between pin REG and V
EE
can be
used to decrease the SLPE voltage while maintaining V
BB
at its nominal value, whereas a resistor connected
between pin REG and pin SLPE will increase the SLPE
voltage while maintaining V
BB
at its nominal value. When
adjusting the SLPE voltage to a lower value, care should
be taken that the V
SLPE
is at least 0.4 V higher than V
BB
(V
BB
supply efficiency).
Fig.5 Supply arrangement.