Le79228
Data Sheet
Features of the Le79228 Quad ISLAC™ Chip Set
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Performs all battery feed, ringing, signaling, hybrid and
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Selectable PCM or GCI interface
test (BORSCHT) functions
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Supports most available master clock frequencies
from 512 kHz to 8.192 MHz
Two chip solution supports high density, multi-channel
architecture
Single hardware design meets multiple country require-
ments through software programming of:
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On-hook transmission
Power/service denial mode
Line-feed characteristics independent of battery voltage
Only 5 V, 3.3 V and battery supplies needed
Low idle-power per line
Linear power-feed with intelligent power-management
feature
Compatible with inexpensive protection networks;
Accommodates low-tolerance fuse resistors while main-
taining longitudinal balance
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Ringing waveform and frequency (for balanced ring-
ing)
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DC loop-feed characteristics and current-limit
Loop-supervision detection thresholds
–Off-hook debounce circuit
–Ground-key and ring-trip filters
Off-hook detect de-bounce interval
Two-wire AC impedance
Transhybrid balance impedance
Transmit and receive gains
Equalization
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Monitors two-wire interface voltages and currents for
subscriber line diagnostics
Tone generation
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DTMF
FSK
Random noise
Arbitrary tone
Digital I/O pins
A-law/µ-law and linear selection
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Supports internal and external battery-backed or earth-
backed ringing
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Built-in voice path test modes
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Self-contained ringing generation and control
Supports external ringing generator and ring relay
Ring relay operation synchronized to zero crossings
of ringing voltage and current
Power-cross, fault, and foreign voltage detection
Meets GR-909 and GR-844 test requirements
Integrated line-test features
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Leakage
Line and ringer capacitance
Loop resistance
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Integrated ring-trip filter and software enabled man-
ual or automatic ring-trip mode
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Supports metering generation with envelope shaping
Smooth or abrupt polarity reversal
Adaptive transhybrid balance
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Integrated self-test features
Echo gain, distortion, and noise
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Small physical size
Up to three relay drivers per VE790 series ISLIC device
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Continuous or adapt and freeze
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Supports both loop-start and ground-start signaling
Exceeds LSSGR and CCITT central office requirements
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Configurable as test load switches
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Zarlink Semiconductor Inc.
ZARLINK [ ZARLINK SEMICONDUCTOR INC ]
