AM79212JC AMD (ADVANCED MICRO DEVICES), AM79212JC Datasheet - Page 12

• Manufacturer Part Number: AM79212JC
• Manufacturer: AMD (ADVANCED MICRO DEVICES)

Specifications of AM79212JC

• Lead Free Status / RoHS Status: Supplier Unconfirmed

ASLIC/ASLAC DEVICES FUNCTIONAL
DESCRIPTION
The ASLIC/ASLAC devices chipset integrates all
functions of the subscriber line. The chipset comprises
an ASLIC device and an ASLAC device. The set
provides two basic functions: 1) the ASLIC device, a
high-voltage, bipolar device that drives the subscriber
line, maintains longitudinal balance, and senses line
conditions, and 2) the ASLAC device, a low-voltage,
CMOS device that combines CODEC, DC Feed control,
and line supervision. A complete schematic of a linecard
using the ASLIC/ASLAC devices chipset is shown in
Figure 7.
The ASLIC device uses reliable, bipolar technology to
provide the power necessary to drive a wide variety of
subscriber lines. It can be programmed by the ASLAC
device to operate in eight different states that control
Power Consumption and Signaling modes. This
enables full control over the subscriber loop. The ASLIC
device is customized to be used exclusively with the
ASLAC device providing a two-chip universal line
interface. The ASLIC device requires only a +5 V power
supply and a negative battery supply for its operation.
The ASLIC device implements a linear loop current
feeding method with the enhancement of thermal
management to limit the amount of power dissipated on
the ASLIC device by dissipating excess power in an
external resistor.
The ASLAC device is a high-performance, CMOS
CODEC/filter device with additional digital filters and
circuits that allow software control of transmission,
DC Feed, and supervision.
Advanced CMOS technology makes the ASLAC device
an economical device that has both the functionality and
the low power consumption required by linecard
designers to maximize linecard density at minimum
cost.
When used with an ASLIC device, the ASLAC device
provides a complete software-configurable solution to
linecard functions as well as complete programmable
control over subscriber line DC Feed characteristics. In
addition, the ASLIC/ASLAC devices chipset provides
system-level solutions for the loop supervisory functions
and metering. In total, the ASLIC/ASLAC devices chipset
provides a programmable solution that can satisfy
worldwide
configuration.
All software-programmed coefficients and DC Feed
parameters are easily calculated with the AmSLAC3
software. This software is provided free of charge and
runs on an IBM-compatible PC. It allows the designer
to enter a description of system requirements, then the
software returns the necessary coefficients and the
predicted system response.
12
linecard
requirements
Am79212/Am79C202 Data Sheet
by
P R E L I M I N A R Y
software
©
The ASLAC device uses the General Control Interface
(GCI) protocol to interface with the back plane highway.
The ASLIC device interface unit inside the ASLAC device
processes information regarding line voltages, loop
currents, and battery voltage levels. These inputs allow
the ASLAC device to place several key ASLIC device
performance
supervision.
The main functions that can be observed and/or controlled
through the ASLAC device control interface are:
To accomplish these functions, the ASLAC device
collects the following information from the ASLIC device
and the Central Office system:
The outputs supplied by the ASLAC device are then:
The ASLAC device performs the CODEC and filter
functions associated with the four-wire section of the
subscriber line circuitry in a digital switch. These
functions involve converting an analog voice signal into
digital PCM samples and converting digital PCM
samples back into an analog signal. During conversion,
digital filters are used to band-limit the voice signals.
The user-programmable filters set the receive and
transmit gain, perform the transhybrid balancing
function, permit adjustment of the two-wire termination
impedance,
DC Feed characteristics
Ground-key detection
Off-hook detection
Metering signal
Longitudinal operating point
Subscriber line voltage and currents
Ring trip
Abrupt and smooth battery polarity reversal
The sum and difference of the currents in each loop
leg, ISUM, and IDIF
Currents proportional to:
— The voltage across the loop (IAB)
— The battery voltage (IBAT)
— The ringing current in the loop (IRTA - IRTB)
A current proportional to the desired DC loop cur-
rent (IDC)
A voltage proportional to the desired longitudinal off-
set voltage (VLBIAS)
A 12/16 kHz metering signal (appears on VM for
12/16 kHz teletax)
and
parameters
provide
frequency
under
programmable
attenuation