am79r70 Advanced Micro Devices, am79r70 Datasheet - Page 2

• Manufacturer Part Number: am79r70
• Description: Ringing Subscriber Line Interface Circuit
• Manufacturer: Advanced Micro Devices

GENERAL DESCRIPTION
The AMD family of subscriber line interface circuit
(SLIC) products provide the telephone interface func-
tions required throughout the worldwide market. AMD
SLIC devices address all major telephony markets in-
cluding central office (CO), private branch exchange
(PBX), digital loop carrier (DLC), fiber-in-the-loop
(FITL), radio-in-the-loop (RITL), hybrid fiber coax
(HFC), and video telephony applications.
The AMD SLIC devices offer support of BORSHT (bat-
tery feed, overvoltage protection, ringing, supervision,
hybrid, and test) functions with features including cur-
rent limiting, on-hook transmission, polarity reversal, tip-
open, and loop-current detection. These features allow
reduction of linecard cost by minimizing component
count, conserving board space, and supporting auto-
mated manufacturing.
The AMD SLIC devices provide the two- to four-wire hy-
brid function, DC loop feed, and two-wire supervision.
Two-wire termination is programmed by a scaled imped-
ance network. Transhybrid balance can be achieved with
an external balance circuit or simply programmed using
a companion AMD codec device, the Am79C02/03/031
DSLAC™ device, the Am79Q02/021/031 Programmable
Quad SLAC (QSLAC™) device, or the Am79Q5457/4457
Nonprogrammable QSLAC device.
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P R E L I M I N A R Y
Am79R70 Data Sheet
The Am79R70 Ringing SLIC device is a bipolar mono-
lithic SLIC that offers on-chip ringing. Now designers
can achieve significant cost reductions at the system
level for short-loop applications by integrating the ring-
ing function on chip. Examples of such applications
would be ISDN Terminal Adaptors and set top boxes.
Using a CMOS-compatible input waveform and wave
shaping R-C network, the Am79R70 Ringing SLIC can
provide trapezoidal wave ringing to meet various de-
sign requirements.
In order to further enhance the suitability of this device
in short-loop, distributed switching applications, AMD
has maximized power savings by incorporating battery
switching on chip. The Am79R70 Ringing SLIC device
switches between two battery supplies such that in the
Off-hook (active) state, a low battery is used to save
power. In order to meet the Open Circuit voltage require-
ments of fax machines and maintenance termination
units (MTU), the SLIC automatically switches to a higher
voltage in the On-hook (standby) state.
Like all of the AMD SLIC devices, the Am79R70 Ringing
SLIC device supports on-hook transmission, ring-trip
detection and programmable loop-detect threshold.
The Am79R70 Ringing SLIC device is a programmable
constant-current feed device with two on-chip relay
drivers to operate external relays. This unique device
is available in the proven AMD 75 V bipolar process in
32-pin PLCC packages.