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

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Output voltage adjustable from −1.2V to −37V

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1.5A output current guaranteed, −55˚C to +150˚C

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Line regulation typically 0.01%/V

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Load regulation typically 0.3%

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Excellent thermal regulation, 0.002%/W

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77 dB ripple rejection

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Excellent rejection of thermal transients

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50 ppm/˚C temperature coefficient

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Temperature-independent current limit

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Internal thermal overload protection

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P

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Standard 3-lead transistor package

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Output is short circuit protected

LM137 Series Packages and Power Capability

Rated

Design

Device

Package

Power

Load

Dissipation

Current

LM137/337

TO-3 (K)

20W

1.5A

TO-39 (H)

2W

0.5A

LM337

TO-220 (T)

15W

1.5A

LM337

SOT-223

(MP)

2W

1A

Typical Applications

Adjustable Negative Voltage Regulator

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Full output current not available at high input-output voltages

†C1=1µF solid tantalum or 10 µF aluminum electrolytic required for

stability

*C2=1µF 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

Comparison between SOT-223 and

D-Pak (TO-252) Packages

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Scale 1:1

November 2004

© 2004 National Semiconductor Corporation

DS009067

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