Le7925
Subscriber Line Interface Circuit
DISTINCTIVE CHARACTERISTICS
I
Control states: Active, Disconnect, and Ringing
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–20 V to –58 V battery operation
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On-hook transmission
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Two-wire impedance set by single external
impedance
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No –5 V supply required
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Fault detectors
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Polarity reversal (active and on-hook)
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Programmable constant-current feed
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Programmable loop-detect threshold
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Programmable ring-trip detect threshold
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Current gain = 500
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On-chip Thermal Management (TMG) feature
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Two on-chip relay drivers and relay snubbers,
one ringing and one general purpose
BLOCK DIAGRAM
TMG
ACO
Fault Detector
ALM
Relay Driver
Ring Relay Driver
RYOUT1
RINGOUT
A(TIP)
Input Decoder
and Control
C1
C2
C3
D1
DET
CS
HPA
Two-Wire Interface
HPB
Signal Transmission
Off-Hook Detector
B(RING)
Power-Feed Controller
VTX
RSN
RD
RDC
CAS
DA
DB
VBAT
BGND
Ring-Trip Detector
VCC
VBREF
AGND
Document ID#
080425
Date:
Rev:
B
Version:
Distribution:
Public Document
Jun 23, 2003
1
ZARLINK [ ZARLINK SEMICONDUCTOR INC ]
