Intelligent Access
™
Voice Solutions
Am79D2251
Dual Intelligent Subscriber Line Audio-Processing Circuit (ISLAC
)
DISTINCTIVE CHARACTERISTICS
s
High performance digital signal processor
provides programmable control of all major
linecard functions
— 32 and 24 kb/s ADPCM to G726, as well as
A-law/
µ
-law and linear codec
— Transmit and receive gain
— Two-wire AC impedance
— Transhybrid balance
— Equalization
— DC loop feeding
— Smooth or abrupt polarity reversal
— Loop supervision
— Off-hook debounce circuit
— Ground-key and ring-trip filters
— Ringing generation and control
— Adaptive hybrid balance
— Line and circuit testing
— Tone generation
— Metering generation at 12 kHz and 16 kHz
— Envelope shaping and level control
s
Selectable PCM/MPI or GCI digital interfaces
— Supports most available master clock
frequencies from 512 kHz to 8.196 MHz
s
0 to 70°C commercial operation
— –40°C to 85°C extended temperature range
available
s
+3.3 V DC operation
s
Exceeds LSSGR and ITU requirements
s
Supports external ringing with on-chip ring-trip
circuit
— Automatic or manual ring-trip modes
s
DTMF detection according to Q.24
s
2100 Hz modem tone detection according to V.25
BLOCK DIAGRAM
A1
ISLIC
7
4
LD1
VREF
VCCA
VCCD
DGND1
B1
RC
Networks
and
Protection
A2
7
3
AGND1
DGND2
AGND2
TSCA/G
P1-P3
ISLIC
LD2
DRA/DD
DXA/DU
DCLK/S0
PCLK/FS
B2
RREF
Dual
ISLAC
5
Ring-Trip
Sense
Resistors
5
MCLK
RSHB
BATH
RSLB
FS/DCL
CS/RST
DIO/S1
BATL
RSPB
BATP
INT
Pub. #
22829
Rev:
C
Amendment:
/0
Issue Date:
December 1999
TABLE OF CONTENTS
Distinctive Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Distinctive Characteristics of The Intelligent Access™ Voice chipset . . . . . . . . . . . . . . . . . . . . . . 3
Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Connection Diagrams. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Pin Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Linecard Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Operating Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Intelligent Access™ Voice Chipsets Environmental Ranges . . . . . . . . . . . . . . . . . . . . 14
Electrical Maximum Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Performance Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Intelligent Access™ Voice Chipsets System Target Specifications . . . . . . . . . . . . . . . . . . . 15
DC Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Transmission and Signaling Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Transmit and Receive Paths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Attenuation Distortion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Group Delay Distortion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Single Frequency Distortion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Intermodulation Distortion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Gain Linearity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Total Distortion Including Quantizing Distortion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Overload Compression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Discrimination against Out-of-Band Input Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Spurious Out-of-Band Signals at the Analog Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Switching Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
PCM Switching Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Microprocessor Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
PCM Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Master Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
PCM Switching Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
GCI Timing Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
GCI Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Physical Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
44-Pin PLCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
44-Pin TQFP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Revision Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Revision A to Revision B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Revision B to Revision C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
2
Am79D2251
The dual ISLAC
device, in combination with an ISLIC
™
device, implements a two channel
universal telephone line interface. This enables the design of a single, low cost, high performance,
fully software programmable line interface for multiple country applications worldwide. All AC, DC,
and signaling parameters are fully programmable via microprocessor or GCI interfaces. Additionally,
the dual ISLAC device has integrated self-test and line-test capabilities to resolve faults to the line
or line circuit. The integrated test capability is crucial for remote applications where dedicated test
hardware is not cost effective.
DISTINCTIVE CHARACTERISTICS OF THE INTELLIGENT ACCESS™ VOICE CHIPSET
s
Performs all battery feed, ringing, signaling,
hybrid and test (BORSCHT) functions
s
Two chip solution supports high density, multi-
channel architecture
s
Single hardware design meets multiple country
requirements through software programming
of:
— Ringing waveform and frequency
— 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
— Transmit and receive gains
— Equalization
— Digital I/O pins
— A-law/µ-law and linear selection
s
Supports internal and external battery-backed
ringing
— 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
— Integrated ring-trip filter and software enabled
manual or automatic ring-trip mode
s
Supports metering generation with envelope
shaping
s
Smooth or abrupt polarity reversal
s
Adaptive transhybrid balance
— Continuous or adapt and freeze
s
Supports both loop-start and ground-start
signaling
s
Exceeds LSSGR and CCITT central office
requirements
s
Selectable PCM or GCI interface
— Supports most available master clock
frequencies from 512 kHz to 8.192 MHz
s
On-hook transmission
s
Power/service denial mode
s
Line-feed characteristics independent of battery
voltage
s
Only 5 V, 3.3 V and battery supplies needed
s
Low idle-power per line
s
Linear power-feed with intelligent power-
management feature
s
Compatible with inexpensive protection
networks; Accommodates low-tolerance fuse
resistors while maintaining longitudinal balance
s
Monitors two-wire interface voltages and
currents for subscriber line diagnostics
s
Built-in voice-path test modes
s
Power-cross, fault, and foreign voltage
detection
s
Integrated line-test features
— Leakage
— Line and ringer capacitance
— Loop resistance
s
Integrated self-test features
— Echo gain, distortion, and noise
s
0 to 70°C commercial operation
— –40°C to 85°C extended temperature range
available
s
Small physical size
s
Up to three relay drivers per ISLIC™ device
— Configurable as test load switches
Am79D2251
3
Figure 1. Dual ISLAC
Block Diagram
IREF
VHL1
VLB1
VOUT1
VINI1
VSAB1
VIMT1
VILG1
XSB1
Ch 1
Converter
Block
VREF
MCLK
FS/DCL
PCLK/FS
Clock and
Reference
Circuits
PCM
and
GCI
Interface
and
Time Slot
Assigner
DXA/DU
DRA/DD
TSCA/G
VHL2
VLB2
VOUT2
VINI2
VSAB2
VIMT2
VILG2
XSB2
LD1
ISLIC
Control
Logic
LD2
P1
P2
P3
Common
External
Sense
Inputs
XSC
SHB
SLB
SPB
Ch 2
Converter
Block
Digital
Signal
Processor
GCI Control
Logic and
Microprocessor
Interface
DCLK/S0
DIO/S1
CS/RST
INT
4
Am79D2251
ORDERING INFORMATION
AMD standard products are available in several packages and operating ranges. The ordering
number (valid combination) is formed by a combination of the elements below. Two ISLIC devices
need to be used with this part.
Am79D2251
J
C
TEMPERATURE RANGE
C= Commercial (0°C to +70°C)
PACKAGE TYPE
J = 44-pin plastic leaded chip carrier (PL044)
V = 44-pin thin plastic quad flat pack (PQT044)
DEVICE NAME/DESCRIPTION
Am79D2251
Advanced Dual Intelligent Subscriber Line Audio-
Processing Circuit
Valid Combinations
Valid Combinations
Am79D2251
Am79D2251
JC
VC
Valid combinations list configurations planned to
be supported in volume for this device. Consult
the local AMD sales office to confirm availability
of specific valid combinations, and to check on
newly released valid combinations.
Am79D2251
5
京公网安备 11010802033920号
EEWORLD
