Voltage References

Subscriber Loop Interface Circuits (SLlC)
MC3419-1L TA = 0° to +70°C, Case 726
The replacement of two-to-four wire conversion hybrid
transformers in Central Office, PBX, and Subscriber Carrier
equipment with the SLiC has resulted in major improvement
in telephone equipment. The SLiC family performs this task,
along with most other BORSHT functions required by signal
• All Key Parameters Externally Programmable
• Current Sensing Outputs Monitor Status of both
Tip and Ring Leads
• On-Hook Power Below 5.0 mW
• Digital Hook Status Output
• Power Down Input
• Ground Fault Protection
• Size and Weight Reduction over Conventional
Approaches
• The sale of this product is licensed under
Patent No. 4,004,109. All royalties related to
this patent are included in the unit price.
MC33120/1 P, FN TA = -40° to +85°C, Case 738, 776
With a guaranteed minimum longitudinal balance of 58 dB,
the MC33120/1 is ideally suited for Central Office applications,
as well as PBXs, and other related equipment. Protection and
sensing components on the two-wire side can be non-precision
while achieving required system performance. Most
BORSHT functions are provided while maintaining low power
consumption, and a cost effective design. Size and weight
reduction over conventional transformer designs permit a
higher density system.
• All key parameters externally programmable with resistors:
• Transmit and Receive Gains
• T ranshybrid Loss
MC33122 TA = -40° to +85°C, Case 'TBD
The MC33122 is designed to provide the interface between
the four-wire side of a Central Office or remote terminal and the
two-wire subscriber line. Interface functions include battery
feed, proper loop termination AC impedance, adjustable
transmit, receive and transhybrid gains, hookswitch and ring
trip detection. Additionally, the MC33122 provides a minimum
of 58 dB of longitudinal balance.
The transmit and receive signals are referenced to analog
ground (VAG), easing the interface to Codecs, filters, etc. The
logic interface is TTL and CMOS compatible.
Internal loop current power transistors sink and source
current attip and ring. Thermal shutdown is provided to protect
against line faults. A switching regulator is used to reduce
power dissipation and enhance reliability, and a clock input
allows synchronization to minimize noise.
The MC33122 will be fabricated on a standard high voltage
(90 V) BiMOS process to increase protection during lightning
surges. It will be available in a 52 pin PLCC and 64 pin QFP
package.
transmission. These include the provision of DC power to the
telephone (Battery); Overvoltage protection; Ring trip
detection; Supervisory features such as hook status and dial
pulsing; 2-to-4 wire conversion, suppression of longitudinal
signals (Hybrid).
Vee
VEE VOB
MOTOROLA LINEAR/INTERFACE ICs DEVICE DATA
8-7
• Return Loss
• DC Loop Current Limit and Battery Feed Resistance
• Longitudinal Impedance
• Single and Double Fault Sensing and Protection
• Minimum 58 dB Longitudinal Balance (2-wire and 4-wire)
Guaranteed
• Digital Hook Status and Fault Outputs
• Power Down Input
• Loop Start or Ground Start Operation
• Size & Weight Reduction Over Conventional Approaches
• Available in 20 Pin DIP and 28 Pin PLCC Packages
• Battery Voltage: -42 V to -58 V (for MC33120),
-21.6 V to -42 V (for MC33121)
• Designed in Accordance with TR·000057 and TA-000909
Bellcore Objectives
• Suitable for CO, Digital Loop Carrier Systems (DLCS),
and PBX
• Full On-Hook Transmission Capability
• On-Chip Loop Current Power Transistors
• Reduced Power Dissipation with Switching Regulator
• Minimum 58 dB Longitudinal Balance
• Externally Adjustable Impedance, Tx, Rx and Transhybrid
Gains
• Current Limit Externally Adjustable to 50 mA
• Hook Switch Detection and Ring Tip Capability,
Adjustable
o Polarity Reversal and Power Down Capability
• Ground Start Sequence Controls
• Two Relay Drivers