TL H 7767
LM120LM320
Series
3-Terminal
Negative
Regulators
November 1994
LM120 LM320
Series 3-Terminal Negative Regulators
General Description
The LM120 series are three-terminal negative regulators
with a fixed output voltage of
b
5V
b
12V and
b
15V and
up to 1 5A load current capability Where other voltages are
required the LM137 and LM137HV series provide an output
voltage range of
b
1 2V to
b
47V
The LM120 need only one external component
a compen-
sation capacitor at the output making them easy to apply
Worst case guarantees on output voltage deviation due to
any combination of line load or temperature variation as-
sure satisfactory system operation
Exceptional effort has been made to make the LM120 Se-
ries immune to overload conditions The regulators have
current limiting which is independent of temperature com-
bined with thermal overload protection Internal current limit-
ing protects against momentary faults while thermal shut-
down prevents junction temperatures from exceeding safe
limits during prolonged overloads
Although primarily intended for fixed output voltage applica-
tions the LM120 Series may be programmed for higher out-
put voltages with a simple resistive divider The low quies-
cent drain current of the devices allows this technique to be
used with good regulation
Features
Y
Preset output voltage error less than
g
3%
Y
Preset current limit
Y
Internal thermal shutdown
Y
Operates with input-output voltage differential down to
1V
Y
Excellent ripple rejection
Y
Low temperature drift
Y
Easily adjustable to higher output voltage
LM120 Series Packages and Power Capability
Rated
Design
Device
Package
Power
Load
Dissipation
Current
LM120 LM320
TO-3 (K)
20W
1 5A
TO-39 (H)
2W
0 5A
LM320
TO-220 (T)
15W
1 5A
LM320M
TO-202 (P)
7 5W
0 5A
Typical Applications
Dual Trimmed Supply
TL H 7767 3
Fixed Regulator
TL H 7767 2
Required if regulator is separated from filter capacitor by more than 3
For
value given capacitor must be solid tantalum 25 mF aluminum electrolytic
may be substituted
Required for stability For value given capacitor must be solid tantalum 25
m
F aluminum electrolytic may substituted Values given may be increased
without limit
For output capacitance in excess of 100 mF a high current diode from
input to output (1N4001 etc ) will protect the regulator from momentary
input shorts
C1995 National Semiconductor Corporation
RRD-B30M115 Printed in U S A
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