UBA1707 NXP Semiconductors, UBA1707 Datasheet - Page 11

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

Philips Semiconductors
The EHI input can also be used for pulse dialling or
register recall (timed loop break). During line breaks
(voltage at pin EHI is LOW or open-circuit), the voltage
regulator is switched off and the capacitor at pin REG is
internally disconnected to prevent its discharge. As a
result, the voltage stabilizer will have negligible switch-on
delay after line interruptions. This minimizes the
contribution of the IC to the current waveform during pulse
dialling or register recall.
When the UBA1707 is in power-down mode (bit PD at
logic 1), the TP
whatever the voltage applied at pin EHI.
S
In the audio frequency range, the dynamic impedance
between pins LN and GND (illustrated in Fig.8) is mainly
determined by the Z
The impedance introduced by the external TN
connected between pin GND and the negative line
terminal (LN ) is negligible.
1999 Feb 17
handbook, halfpage
ET IMPEDANCE
Cordless telephone, answering machine
line interface
L
R
Fig.8
eq
P
= internal resistance = 35 k .
= C
REG
Equivalent impedance between
LN and GND.
GND
R
LN
SLPE
SLPE
DARL
R
SET
transistor is forced to be turned off
P
L EQ
R SLPE
10
V ref
impedance.
REG
R P
4.7 F
C REG
MGL215
619
Z SET
SW
transistor
11
T
The UBA1707 has symmetrical transmit inputs TXI+ and
TXI . The input impedance between pins TXI+ or TXI and
GND is 21 k . The voltage gain from pins TXI+ or TXI to
pin LN is set at 11.6 dB with 600
619
2
Automatic gain control is provided on this amplifier for line
loss compensation.
R
The receive amplifier (see Fig.9) has one input (RXI) and
one output (RXO). The input impedance between pins
RXI and GND is 21 k . The rail-to-rail output stage is
designed to drive a 500 A peak current. The output
impedance at pin RXO is approximately 100 .
The voltage gain from pin RXI to pin RXO is set at 37.9 dB.
This gain value compensates typically the attenuation of
the anti-sidetone network (see Fig.10). The output as well
as the input are biased at 2
control is provided on this amplifier for line loss
compensation. This amplifier can be muted by activating
the receive mute function (bit RXM at logic 1).
RANSMIT AMPLIFIER
ECEIVE AMPLIFIER
V
d
set impedance. The inputs are biased at
1.4 V, with V
(
PINS
(
PINS
d
representing the diode voltage.
RXI
TXI+
AND
V
d
AND
RXO;
1.4 V. Automatic gain
line load (Z
TXI )
Product specification
BIT
UBA1707
RXM)
line
) and