January 1995
LM145/LM345 Negative Three Amp Regulator
General Description
The LM145 is a three-terminal negative regulator with a
current of the device allows this technique to be used with
good regulation.
b
fixed output voltage of 5V and up to 3A load current capa-
bility. This device needs only one external componentÐa
compensation capacitor at the output, making it easy to ap-
ply. Worst case guarantees on output voltage deviation due
to any combination of line, load or temperature variation
assure satisfactory system operation.
The LM145 comes in a hermetic TO-3 package rated at
25W. A reduced temperature range part LM345 is also avail-
able.
Features
Y
Exceptional effort has been made to make the LM145 im-
mune to overload conditions. The regulator has current lim-
iting which is independent of temperature, combined with
thermal overload protection. Internal current limiting pro-
tects against momentary faults while thermal shutdown pre-
vents junction temperatures from exceeding safe limits dur-
ing prolonged overloads.
g
Output voltage accurate to better than 2%
Y
Y
Y
Current limit constant with temperature
Internal thermal shutdown protection
Operates with input-output voltage differential of 2.8V at
full rated load over full temperature range
Regulation guaranteed with 25W power dissipation
3A output current guaranteed
Y
Y
Y
Y
Although primarily intended for fixed output voltage applica-
tions, the LM145 may be programmed for higher output volt-
ages with a simple resistive divider. The low quiescent drain
Only one external component needed
Pa Product Enhancement tested
Schematic Diagram
TL/H/7785–1
C
1995 National Semiconductor Corporation
TL/H/7785
RRD-B30M115/Printed in U. S. A.