AM79R251 Datasheet, PDF (1/27 Pages) Advanced Micro Devices – Intelligent Subscriber Line Interface Circuit (ISLIC)

Intelligent Access™ Voice Solutions
Am79R251
Intelligent Subscriber Line Interface Circuit (ISLIC™)
DISTINCTIVE CHARACTERISTICS
s Monitor of two-wire interface voltages and
currents supports
— Voice transmission
— Through chip ring generation
— Programmable DC feed characteristics
— Independent of battery
— Current limited
— Selectable off-hook and ground-key thresholds
— Subscriber line diagnostics
— Leakage resistance
— Loop resistance
— Line capacitance
— Bell capacitance
— Foreign voltage sensing
— Power cross and fault detection
BLOCK DIAGRAM
s Supports internal and external ringing
— High voltage operation supports long loops
s +5 V and battery supplies
s Dual battery operation for system power saving
— Automatic battery switching
— Intelligent thermal management
s Compatible with inexpensive protection
networks
— Accommodates low tolerance fuse resistors or
PTC thermistors
s Metering capable
— 12 kHz and 16 kHz
— Smooth polarity reversal
s Tip-open state supports ground start signaling
s Integrated test load switches/relay drivers
AD
SA
HPA
HPB
SB
BD
Two-Wire
Interface
Longitudinal
Control
TMN
TMP
TMS
VBP
VBL
VBH
R2
R3
RYE
R1
Thermal
Management
Control
Fault
Meas
Switch
Driver
Relay
Drivers
Relay Control
Input Decoder and
Control Registers
Relay
Driver 1
Signal
Transmission
Gain/Level Shift
Attenuator
Signal
Conditioning
RSN
VTX
VLB
VSAB
VREF
IMT
ILG
CREF
P1
P2
P3
LD
BGND
GND
VCC
Pub. # 22480 Rev: C Amendment: /0
Issue Date: December 1999