Intelligent Access
ä
Voice Solutions
Am79231
Intelligent Subscriber Line Interface Circuit (ISLIC
™
)
DISTINCTIVE CHARACTERISTICS
BLOCK DIAGRAM
AD
SA
HPA
HPB
SB
BD
Two-Wire
Interface
TMN
TMP
TMS
Thermal
Management
Control
Fault
Meas.
VBL
Switch
Driver
VBH
R2
R3
RYE
Relay
Drivers
Relay Control
Input Decoder and
Control Registers
R1
Relay
Driver 1
BGND
GND
— Voice transmission
— 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
Monitor of two-wire interface voltages and
currents supports
+5 V and battery supplies
Dual battery operation for system power saving
— Automatic battery switching
— Intelligent thermal management
Compatible with inexpensive protection
networks
— Accommodates low tolerance fuse resistors or
PTC thermistors
Metering capable
— 12 kHz and 16 kHz
— Smooth polarity reversal
Tip-open state supports ground start signaling
Ring relay driver for external ringing
Integrated test load switches/relay drivers
Signal
Transmission
RSN
VTX
Longitudinal
Control
Gain/Level Shift
VLB
Attenuator
VSAB
VREF
Signal
Conditioning
IMT
ILG
CREF
P1
P2
P3
LD
VCC
Pub. #
080248
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
Block Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Connection Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Pin Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Intelligent Access™ Voice Chipsets Linecard With Am79231 . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Linecard Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Thermal Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Operating Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Environmental Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Electrical Maximum Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Target Specifications (See note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Relay Driver Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Am79231 Transmission Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Am79231 Current-Limit Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Am79231 Fault Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Thermal-Management Equations (All Modes except Standby) . . . . . . . . . . . . . . . . . . 21
Timing Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Physical Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
PL032 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Revision Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Revision A to Revision B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Revision B to Revision C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
2
Am79231 Data Sheet
The Am79231, in combination with an ISLAC
™
device, implements the telephone line interface
function. This enables the design of a 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 on the ISLAC device. Additionally, the Am79231
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.
Performs all battery feed, ring-trip, signaling,
hybrid and test (BORSCHT) functions
Two chip solution supports high density, multi-
channel architecture
Single hardware design meets multiple country
requirements through software programming of:
— 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
Supports external battery-backed ringing
— Unbalanced ringing
— Ring relay driver
— Ring relay operation synchronized to zero cross-
ings of ringing voltage and current
— Integrated ring-trip filter and software enabled
manual or automatic ring-trip mode
Supports metering generation with envelope
shaping
Smooth or abrupt polarity reversal
Adaptive transhybrid balance
— Continuous or adapt and freeze
Supports both loop-start and ground-start
signaling
Am79231 Data Sheet
DISTINCTIVE CHARACTERISTICS OF THE
INTELLIGENT ACCESS™ VOICE CHIPSET
Exceeds LSSGR and CCITT central office
requirements
Selectable PCM or GCI interface
— Supports most available master clock frequen-
cies from 512 kHz to 8.192 MHz
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 maintaining longitudinal balance
Monitors two-wire interface voltages and
currents for subscriber line diagnostics
Built-in voice-path test modes
Power-cross, fault, and foreign voltage detection
Integrated line-test features
— Leakage
— Line and ringer capacitance
— Loop resistance
Integrated self-test features
— Echo gain, distortion, and noise
0 to 70°C commercial operation
— –40°C to 85°C extended temperature range
available
Small physical size
Up to three relay drivers per ISLIC
™
device
— Configurable as test load switches
3
BLOCK DIAGRAMS
Figure 1.
Example Four-Channel Linecard Block Diagram
4
7
VCCA
VCCD
DGND1
DGND2
A1
B1
Am79231
VREF
LD1
A2
B2
A3
B3
7
RC
Networks
and
Protection
Am79231
LD2
AGND1
AGND2
7
4
IO1-IO4
TSCA/G
TSCB
DRA/DD
Am79231
3
LD3
P1-P3
A4
Am79231
B4
7
LD4
Quad
ISLAC
Am79Q2243
DRB
DXB
DXA/DU
DCLK/S0
RREF
5
Ring-Trip
Sense
Resistors
5
PCLK/FS
MCLK
RSHB
BATH
RSLB
FS/DCL
CS/RST
BATL
DIO/S1
INT
4
Am79231 Data Sheet
Figure 2.
Am79231 Block Diagram
A Amplifier
AD
IA
SA
IA sense
IA
600
+
Fault
Meas.
-
+
-
RSN
HPA
+
VTX
TMS
BGND
HPB
Fault
Meas.
SB
IB
BD
VREF
+
-
-
+
+
β = 0.01
-
VSAB
B Amplifier
IB sense
IB
600
VREF
VREF
TMN
VREF
TMP
Thermal
Management
Control
To Power
Amplifiers
High Neg.
Bat. sel.
Gain/Level Shift
VLB
Thermal
Shutdown
VBH
IA
IB
+
600 600
OHT Fixed Longitudinal
Voltage
Active High Battery
Active Low Battery
VBL
R3
IMT
IA
IB
−
600 600
Disconnect
Tip Open
ILG
Reserved
RYE
R2
RD1
R1
Power amplifiers positive supply
RD2
Decoder
CREF
RD3
C1
C2
Control Register
C3
Demux
P1
P2
P3
LD
VCC
GND
BGND
Am79231 Data Sheet
Standby
5
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