LM320L/LM79LXXAC Series 3-Terminal Negative Regulators
February 2005
LM320L/LM79LXXAC Series
3-Terminal Negative Regulators
General Description
The LM320L/LM79LXXAC dual marked series of 3-terminal
negative voltage regulators features fixed output voltages of
−5V, −12V, and −15V with output current capabilities in
excess of 100mA. These devices were designed using the
latest computer techniques for optimizing the packaged IC
thermal/electrical performance. The LM79LXXAC series,
even when combined with a minimum output compensation
capacitor of 0.1µF, exhibits an excellent transient response,
a maximum line regulation of 0.07% V
O
/V, and a maximum
load regulation of 0.01% V
O
/mA.
The LM320L/LM79LXXAC series also includes, as self-
protection circuitry: safe operating area circuitry for output
transistor power dissipation limiting, a temperature indepen-
dent short circuit current limit for peak output current limiting,
and a thermal shutdown circuit to prevent excessive junction
temperature. Although designed primarily as fixed voltage
regulators, these devices may be combined with simple
external circuitry for boosted and/or adjustable voltages and
currents. The LM79LXXAC series is available in the 3-lead
TO-92 package, 8-lead SOIC package, and the 6-Bump
micro SMD package. The LM320L series is available in the
3-lead TO-92 package.
For output voltage other than −5V, −12V and −15V, the
LM137L series provides an output voltage range from 1.2V
to 47V.
Features
n
Preset output voltage error is less than
±
5% overload,
line and temperature
n
Specified at an output current of 100mA
n
Easily compensated with a small 0.1µF output
capacitor
n
Internal short-circuit, thermal and safe operating area
protection
n
Easily adjustable to higher output voltages
n
Maximum line regulation less than 0.07% V
OUT
/V
n
Maximum load regulation less than 0.01% V
OUT
/mA
n
See AN-1112 for micro SMD considerations
Typical Applications
Fixed Output Regulator
Adjustable Output Regulator
00774801
00774803
*Required if the regulator is located far from the power supply filter. A 1µF
aluminum electrolytic may be substituted.
*
*
Required for stability. A 1µF aluminum electrolytic may be substituted.
−V
0
= −5V − (5V/R1 + I
Q
)
•
R2,
5V/R1
>
3 I
Q
Connection Diagrams
6-Bump micro SMD
TO-92 Plastic Package (Z)
00774802
Bottom View
00774820
Bump Side Down
© 2005 National Semiconductor Corporation
DS007748
www.national.com
NSC [ NATIONAL SEMICONDUCTOR ]
