UBA1707 NXP Semiconductors, UBA1707 Datasheet - Page 6

• Manufacturer Part Number: UBA1707
• Description: Cordless Telephone, Answering Machine Line Interface
• Manufacturer: NXP Semiconductors

Philips Semiconductors
FUNCTIONAL DESCRIPTION
All data given in this chapter are typical values, except
when otherwise specified.
Supply (pins V
The UBA1707 must be supplied with an external stabilized
voltage source between pins V
Pins GND and LSPGND must be connected together.
Without any signal, with the loudspeaker channel enabled
at minimum volume and without any general purpose
switch selected, the internal current consumption is
2.2 mA at V
(pins SWI1, SWI2, or SWI3) increases the current
consumption by 600 A.
The supply current can be reduced when the loudspeaker
channel is not used by switching it off (bit LSPD at logic 1).
The current consumption is then decreased by
approximately 800 A at minimum volume.
To drastically reduce current consumption, the UBA1707
is provided with a power-down mode controlled by bit PD.
When bit PD is at logic 1, the current consumption from
V
the only function which remains active.
Line interface
DC
LCC, RGL
The IC generates a stabilized reference voltage (V
between pins LN and SLPE. This reference voltage is
equal to 2.9 V, is temperature compensated and can be
adjusted by means of an external resistor (R
increased by connecting the R
pins REG and SLPE (see Fig.3).
The voltage at pin REG is used by the internal regulator to
generate the stabilized reference voltage and is decoupled
by a capacitor (C
capacitor, converted into an equivalent inductance
(see Section “Set impedance”) realizes the set impedance
conversion from its DC value (R
(Z
the reference voltage supply configuration. As can be seen
from Fig.4, part of the line current flows into the Z
impedance network and is not sensed by the UBA1707.
Therefore using the R
reference voltage will also modify all parameters related to
the line current such as:
1999 Feb 17
CC
SET
Cordless telephone, answering machine
line interface
CHARACTERISTICS
becomes 110 A. In this mode, the serial interface is
in the audio-frequency range). Figure 4 illustrates
AND
CC
= 3.3 V. Each selected switch
GND;
CC
REG
and GND; bits PD and LSPD)
) which is connected to GND. This
(
BIT
VA
PINS
resistor to change value of the
CRC)
LN, SLPE, REG, CST, LVI,
VA
CC
SLPE
resistor between
and GND.
) to its AC value
VA
). It can be
SET
ref
)
6
In the same way, changing the value of Z
the characteristics. The IC has been optimized for
V
The IC regulates the line voltage at pin LN which can be
calculated as follows:
Where:
The preferred value for R
affect more than the DC characteristics; it also influences
the transmit gain, the gain control characteristics, the
sidetone level and the maximum output swing on the line.
However, for compliance with CTR 21 8.66
value for R
V
I
handbook, halfpage
SLPE
ref
LN
The automatic gain control
The DC mask management
The low voltage area characteristics.
I
I
I* = current consumed between LN and GND
(approximately 100 A).
line
ZSET
(1) Influence of R
(2) V
V ref
= 2.9 V and Z
(V)
=
Fig.3 Reference voltage adjustment with R
= line current
=
8.5
7.5
6.5
5.5
4.5
3.5
2.5
V
= current flowing through Z
ref
10
I
ref
line
without influence of R
3
SLPE
+
–
R
I
ZSET
SLPE
.
VA
SET
on V
–
10
= 619 .
I* I
I
SLPE
ref
4
(1)
(2)
.
SLPE
VA
line
.
is 10 . Changing R
–
I
ZSET
10
SET
5
Product specification
R VA ( )
UBA1707
SET
MGK706
also affects
is the best
10
6
VA
SLPE
.
will