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参数资料
| 型号： | PBL386302QNS |
| 厂商： | ERICSSON |
| 英文描述： | Subscriber Line Interface Circuit |
| 中文描述： | 用户线接口电路 |
| 文件页数： | 15/16页 |
| 文件大小： | 134K |
| 代理商： | PBL386302QNS |
PBL 386 30/2
15
The ring trip function is based on a polar-
ity change at the comparator input when
the line goes off-hook. In the on-hook state
no dc current flows through the loop and
the voltage at comparator input DT is more
positive than the voltage at input DR. When
the line goes off-hook, while the ring relay
is energized, dc current flows and the
comparator input voltage reverses polarity.
Figure 11 gives an example of a ring trip
detection network. This network is applica-
ble, when the ring voltage is superimposed
on V
and is injected on the ring lead of the
two-wire port. The dc voltage across sense
resistor R
is monitored by the ring trip
comparator input DT and DR via the net-
work R
, R
, R
, R
, C
and C
. With the line
on-hook (no dc current) DT is more positive
than DR and the DET output will report
logic level high, i.e. the detector is not
tripped. When the line goes off-hook, while
ringing, a dc current will flow through the
loop including sense resistor R
and will
cause input DT to become more negative
than input DR. This changes output DET to
logic level low, i.e. tripped detector condi-
tion. The system controller (or line card
processor) responds by de-energizing the
ring relay, i.e. ring trip.
Complete filtering of the 20 Hz ac com-
ponent at terminal DT and DR is not neces-
sary. A toggling DET output can be exam-
ined by a software routine to deter-mine the
duty cycle. When the DET output is at logic
level low for more than half the time, off-
hook condition is indicated.
Relay driver
The PBL 386 30/2 SLIC incorporates a
ring relay driver designed as open
collector (npn) with a current sinking
capability of 50 mA. The drive transistor
emitter is connected to BGND. The relay
driver has an internal zener diode clamp
for inductive kick-back voltages. Care
must be taken when using the relay
driver together with relays that have high
impedance.
Control Inputs
The PBL 386 30/2 SLIC have two digital
control inputs, C1 and C2.
A decoder in the SLIC interprets the
control input condition and sets up the
commanded operating state.
C1 and C2 are internal pull-up inputs.
Open Circuit State
In the Open Circuit State the TIPX and
RINGX line drive amplifiers as well as other
circuit blocks are powered down. This
causes the SLIC to present a high imped-
ance to the line. Power dissipation is at a
Figure 13. CODEC receive interface.
PBL386 30/2
CODEC
+
_
VTX
RSN
R
RX
R
T
R
R
I
RRX
I
RSN
I
RT
I
RR
U
REFcodec
+1.25 V
I
DC-GND
minimum and no detectors are active.
Ringing State
The ring relay driver and the ring trip detec-
tor are activated and the ring trip detector is
indicating off hook with a logic low level at
the detector output.
The SLIC is in the active normal state.
Active State
TIPX is the terminal closest to ground and
sources loop current while RINGX is the
more negative terminal and sinks loop cur-
rent. Vf signal transmission is normal and
the loop current detector is activated. The
loop current detector is indicating off hook
with a logic low level present at the detector
output.
Overvoltage Protection
The PBL 386 30/2 SLIC must be protected
against overvoltages on the telephone line
caused by lightning, ac power contact and
induction. Refer to Maximum Ratings, TIPX
and RINGX terminals, for maximum allow-
able continuous and transient currents that
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相关代理商/技术参数 |
参数描述 |
|---|---|
| PBL386302QNT | 制造商:ERICSSON 制造商全称:Ericsson 功能描述:Subscriber Line Interface Circuit |
| PBL386302QNTNT | 制造商:Infineon Technologies AG 功能描述:POTS |
| PBL386302SHT | 制造商:ERICSSON 制造商全称:Ericsson 功能描述:Subscriber Line Interface Circuit |
| PBL386302SOAXT | 制造商:Infineon Technologies AG 功能描述:SLIC 1-CH 66dB 45mA 5V 24-Pin DSO T/R |
| PBL386302SOS | 制造商:ERICSSON 制造商全称:Ericsson 功能描述:Subscriber Line Interface Circuit |
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