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參數(shù)資料
| 型號： | LUCL8575BP |
| 英文描述： | Dual-Resistive,Low-Cost Subscriber Line Interface Circuit(SLIC) |
| 中文描述： | 雙電阻，低成本用戶線接口電路（SLIC） |
| 文件頁數(shù)： | 20/36頁 |
| 文件大小： | 633K |
| 代理商： | LUCL8575BP |
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L8575
Dual-Resistive, Low-Cost SLIC
Advance Data Sheet
March 1997
20
Lucent Technologies Inc.
Applications
(continued)
Protection
(continued)
Similar consideration to the individual resistor and total
module power capability should be given to full voltage
power faults, but taking into account the fault detector
will isolate the SLIC and resistor module after some
finite period of time. The fault detector indicates a fault
in the serial data output stream in 10 ns to 30 ms. Rec-
ognition and relay activation time need to be consid-
ered.
Tip/Ring Drivers
Each channel of the L8575 utilizes a current source for
the Tip/Ring driver. The driver is capable of sinking (but
not sourcing) up to 15 mA from the Tip (PT) while
swinging to within 4 V of office battery (V
BAT
), and
sourcing (but not sinking) up to 15 mA to the Ring (PR)
while swinging to within 4 V of ground (AGND). Since
the current driver is not bidirectional, during transmis-
sion (powerup) each lead is biased at 5.6 mAdc.
Receive Interface
The receive interface circuitry couples the differential
signal on receive inputs IRP and VRN to the Tip/Ring
drivers. Input IRP is a low-impedance (<5
) current
input while VRN is a high-impedance voltage input.
Internal feedback forces the voltage at IRP to be equal
to VRN such that a voltage applied to VRN causes a
current flow out of IRP, which equals that voltage
divided by the impedance connected from IRP to
AGND (assuming the input voltage is referenced to
AGND).
The receive interface and Tip/Ring drivers provide a
current gain of 200, i.e., a differential output current
flows from PT to PR which is 200 times the current
flowing into IRP. The receive interface also provides a
level shift since the inputs, IRP and VRN, are refer-
enced to analog ground, while the outputs, PT and PR,
swing between AGND and V
BAT
. The receive interface
ensures that the input current is not converted to a
common-mode current at PT and PR.
Transmit Interface
The transmit interface circuitry interfaces the differen-
tial voltage on Tip and Ring to transmit output XMT. The
Tip/Ring differential voltage (both ac and dc) appears
on output XMT with a gain of 0.5.
The transmit interface uses an operational amplifier
with four external resistors to perform a differential to
single-ended conversion. Output XMT is referenced to
ground (AGND). The longitudinal balance and gain
accuracy at XMT depends on the matching of the
external resistors.
Because a large dc potential exists at XMT, a capacitor
must be used to couple the ac signal to the low-voltage
codec circuitry. The operational amplifier inputs are TS
and RS. These inputs are also used by the fault-detec-
tion circuitry to detect fault voltages on Tip or Ring. A
fault is detected when the magnitude of the voltage
across either dc feed resistor exceeds a nominal 36 V
(equivalent to approximately 4 W dissipation in either
resistor). A delay is provided (using an external capaci-
tor on pin CFLT) in the fault detector. This prevents
transients on Tip and Ring from tripping the fault detec-
tor when a fault is not actually present.
Battery Noise Cancellation
The battery noise cancellation circuit senses the ac
noise on the battery via the capacitor connected
from input CBN to V
BAT
. It then couples this noise,
180 degrees out of phase, to the Ring current driver
amplifier. This cancels the battery noise that is coupled
to the Ring through the feed resistor connected to V
BAT
.
Additionally, it ensures longitudinal balance which
depends only on the matching of the battery feed resis-
tors by creating an ac ground at V
BAT
with respect to
signals on the Ring lead.
For the cancellation to operate properly, both the phase
and gain must be accurate. The battery noise cancella-
tion gain is a transconductance that is equal to 50
divided by resistor R9 on the thick film resistor module
connected from RGBN to ground (AGND). This value
must be equal to the reciprocal of the dc feed resistor
(1/300
), that is,
It is advantageous if the two resistors are matched and
tracked thermally, i.e., located on the same film inte-
grated circuit (FIC).
9
R
9
R
15 k
300
=
=
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LUCL8575BP-TR | Dual-Resistive,Low-Cost Subscriber Line Interface Circuit(SLIC) |
| LUCL8576BP-D | Dual Ringing SLIC |
| LUCL8576BP-DT | Dual Ringing SLIC |
| LUCL9214AAJ-D | GT 19C 19#12 PIN RECP |
| LUCL9214AAJ-DT | Circular Connector; MIL SPEC:MIL-C-5015; Body Material:Metal; Series:GT; No. of Contacts:2; Connector Shell Size:24; Connecting Termination:Solder; Circular Shell Style:Square Flange Receptacle; Body Style:Straight |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LUCL8575BP-TR | 制造商:AGERE 制造商全稱:AGERE 功能描述:Dual-Resistive,Low-Cost Subscriber Line Interface Circuit(SLIC) |
| LUCL8576BP-D | 制造商:AGERE 制造商全稱:AGERE 功能描述:Dual Ringing SLIC |
| LUCL8576BP-DT | 制造商:AGERE 制造商全稱:AGERE 功能描述:Dual Ringing SLIC |
| LUCL9214AA-DT | 制造商:AGERE 制造商全稱:AGERE 功能描述:Low-Cost Ringing SLIC |
| LUCL9214AAJ-D | 制造商:AGERE 制造商全稱:AGERE 功能描述:Low-Cost Ringing SLIC |
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