MC33121 Datasheet, PDF (1/32 Pages) Motorola, Inc – LOW VOLTAGE SUBSCRIBER LOOP INTERFACE CIRCUIT

MOTOROLA
SEMICONDUCTOR TECHNICAL DATA
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by MC33121/D
MC33121
Low Voltage Subscriber
Loop Interface Circuit (SLIC)
Thin Film Silicon Monolithic Integrated Circuit
The MC33121 is designed to provide the interface between the 4–wire side of
a central office, or PBX, and the 2–wire subscriber line. Interface functions
include battery feed, proper loop termination AC impedance, hookswitch
detection, adjustable transmit, receive, and transhybrid gains, and single/
double fault indication. Additionally, the MC33121 provides a minimum of 58 dB
of longitudinal balance (4–wire and 2–wire).
The transmit and receive signals are referenced to analog ground, while
digital signals are referenced to digital ground, easing the interface to codecs,
filters, etc. The 2 status outputs (hookswitch and faults) and the Power Down
Input are TTL/CMOS compatible. The Power Down Input permits local
shutdown of the circuit.
Internal drivers allow the external loop current pass transistors to be standard
bipolar transistors (non–Darlington).
The MC33121 is available in a 20 pin DIP and a 28 pin PLCC surface mount
package.
• 58 dB Longitudinal Balance Guaranteed; 4–wire and 2–wire
• Transmit, Receive, and Transhybrid Gains Externally Adjustable
• Return Loss Externally Adjustable
• Proper Hookswitch Detection With 30 kΩ Leakage
• Single/Double Fault Indication With Shutdown for Thermal Protection
• Critical Sense Resistors Included Internally
• Standard Power Supplies: – 21.6 V to – 42 V, and + 5.0 V, ± 10%
• On–Hook Transmission
• Power Down Input (TTL and CMOS Compatible)
• Operating Ambient Temperature: – 40°C to + 85°C
• Available in a 20 Pin DIP and 28 Pin PLCC Package
20
1
28
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P SUFFIX
PLASTIC PACKAGE
CASE 738
FN SUFFIX
PLCC
CASE 776
ORDERING INFORMATION
Device
Temperature
Range
Package
MC33121P
Plastic DIP
– 40° to + 85°C
MC33121FN
PLCC
VCC
EP
BP
TIP
CP
TSI
RSI
RING
CN
BN
EN
VEE
(BATTERY)
*
–
+
VEE
VCC
–
+
*
SIMPLIFIED BLOCK DIAGRAM
CURRENT
MIRROR
CURRENT
MIRROR
CURRENT
MIRROR
*
*
CURRENT
MIRROR
HOOK STATUS AND
FAULT DETECTION
AND BIAS CONTROL
CURRENT
MIRROR
CURRENT
MIRROR
+
–
BIAS
+
–
MC33121
VDD (+5.0 V)
VDG
(DIG. GND)
PDI/ST2
ST1
VAG
(ANA. GND)
RXI
TXO
RFO
CF
VQB
* Indicates trimmed resistor
REV 1.0
4/96
©_MOMo_Tto_Oro_Rla,_OIn_Lc._A1996
MC33121
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