General Description; Typical Applications - Harman Kardon HK 990/230 Service Manual

LM137/LM337
3-Terminal Adjustable Negative Regulators

General Description

The LM137/LM337 are adjustable 3-terminal negative volt-
age regulators capable of supplying in excess of −1.5A over
an output voltage range of −1.2V to −37V. These regulators
are exceptionally easy to apply, requiring only 2 external
resistors to set the output voltage and 1 output capacitor for
frequency compensation. The circuit design has been opti-
mized for excellent regulation and low thermal transients.
Further, the LM137 series features internal current limiting,
thermal shutdown and safe-area compensation, making
them virtually blowout-proof against overloads.
The LM137/LM337 serve a wide variety of applications in-
cluding local on-card regulation, programmable-output volt-
age regulation or precision current regulation. The LM137/
LM337 are ideal complements to the LM117/LM317
adjustable positive regulators.
Features
n Output voltage adjustable from −1.2V to −37V
n 1.5A output current guaranteed, −55˚C to +150˚C
n Line regulation typically 0.01%/V
n Load regulation typically 0.3%

Typical Applications

Adjustable Negative Voltage Regulator
Full output current not available at high input-output voltages
†
C1 = 1 µF solid tantalum or 10 µF aluminum electrolytic required for
stability
*C2 = 1 µF solid tantalum is required only if regulator is more than 4" from
power-supply filter capacitor
Output capacitors in the range of 1 µF to 1000 µF of aluminum or tantalum
electrolytic are commonly used to provide improved output impedance and
rejection of transients
© 2004 National Semiconductor Corporation
n Excellent thermal regulation, 0.002%/W
n 77 dB ripple rejection
n Excellent rejection of thermal transients
n 50 ppm/˚C temperature coefficient
n Temperature-independent current limit
n Internal thermal overload protection
n P
n Standard 3-lead transistor package
n Output is short circuit protected
LM137/337
LM337
LM337
Comparison between SOT-223 and
D-Pak (TO-252) Packages
00906701
DS009067
18
+
Product Enhancement tested
LM137 Series Packages and Power Capability
Device Package
TO-3 (K)
TO-39 (H)
TO-220 (T)
SOT-223
(MP)
Scale 1:1
November 2004
Rated Design
Power Load
Dissipation Current
20W 1.5A
2W 0.5A
15W 1.5A
2W 1A
00906731
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