LM337 is an adjustable negative voltage regulator IC.
This blog describes LM337 pinout, circuit, equivalent, features, where and how to use this ic and other important details.
Catalog
LM337 Description
LM337 is an adjustable 3-terminal negative-voltage regulator capable of supplying in excess of –1.5A over an output voltage range of –1.2V to –37V. It requires only two external resistors to set the output voltage and one output capacitor for frequency compensation.
As a negative voltage regulator IC, LM337 is complementary to LM317 positive voltage regulator. LM337 have many built in features like overheat shutdown, overcurrent shutdown, short circuit protection etc. which makes the IC damage proof in many situations.
The IC will dissipate heat during operation because all the voltage difference will convert to heat and a suitable heat sink is must to use with the IC.
LM337 Pinout
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LM337 voltage regulator |
LM337 voltage regulator pinout |
Pin Number |
Pin Name |
Description |
1 |
Adjust |
This pins adjusts the output voltage |
2 |
Input Voltage (Vin) |
The input voltage which has to be regulated is given to this pin |
3 |
Output Voltage (Vout) |
The regulated output voltage set by the adjust pin can be obtained from this pin |
LM337 Features
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Adjustable 3-terminal Negative voltage regulator
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Output voltage can be set to range from -1.25V to -37V
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Maximum Output current is -1.5A
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Differential Input and Output Voltage is 40V(max), recommended 15V
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Maximum output current when voltage difference is 15V is -2.2A
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Operating junction temperature is 125°C
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Available in To-220, SOT223, TO263 Package
LM337 Parameter
Manufacturer: |
Texas Instruments |
Series: |
- |
Packaging: |
Tube |
Part Status: |
Active |
Output Configuration: |
Negative |
Output Type: |
Adjustable |
Number of Regulators: |
1 |
Voltage - Input (Max): |
-40V |
Voltage - Output (Min/Fixed): |
-1.2V |
Voltage - Output (Max): |
-37V |
Voltage Dropout (Max): |
- |
Current - Output: |
1.5A |
PSRR: |
77dB (120Hz) |
Control Features: |
- |
Protection Features: |
Over Temperature Short Circuit |
Operating Temperature: |
0°C ~ 125°C |
Mounting Type: |
Through Hole |
Package / Case: |
TO-220-3 |
Supplier Device Package: |
TO-220-3 |
Base Part Number: |
LM337 |
LM337 Equivalent
LT137, PB137, LM317 (Positive Variable Voltage regulator), L7915CV
LM337 Circuit
The schematic below shows an adjustable negative-voltage regulator circuit based on the LM337 IC. The circuit's input voltage ranges from -3V to 40V DC, and the output voltage ranges from -1.25V to -37V.
LM337 adjustable negative voltage regulator circuit
Where & How to use LM337
Depending on the user's needs, the LM337 can be used as an adjustable or fixed regulator. The output can be adjusted using a resistor divider network connected to the IC's adjustment pin.
In the resistor divider network, a variable resistor can also be used to easily adjust the output voltage to the desired level. This IC can also be used as a fixed output negative voltage regulator; simply replace the variable resistor with a fixed value resistor based on the output voltage.
There are a lot of online calculators that can be used to calculate the resistor value of the desired output voltage. The ic can be used in a variety of power supply and battery charger applications. The input voltage must be 2V to 3V higher than the output voltage for this IC to produce a stable output voltage.
How to safely long run LM337 in a circuit
To achieve long-term stable performance with the LM337, do not apply a load greater than 1.5A or a voltage higher than 37V. Input voltage should not exceed 40V. Use a suitable heat sink with the IC and operate it at temperatures above -40 degrees Celsius and below +125 degrees Celsius at all times. The storage temperature should be higher than -60 degrees Celsius and lower than +150 degrees Celsius.
LM337 Application
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Used for Positive voltage regulations
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Variable power supply
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Current limiting circuits
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Reverse polarity circuits
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Commonly used in Desktop PC, DVD and other consumer products
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Used in motor control circuits
LM337 Package
Component Datasheet
FAQ
The LM337 is a negative adjustable voltage regulator which can output a range of voltages from -1.5V to -38V based on the resistors R1 and R2. The resistor R2 then is the chief resistor which allows for the swings in different voltage outputs. |
- What is the range of the voltage level of the LM337 adjusted voltage regulator?
The LM337 series are adjustable 3-terminal negative voltage regulators capable of supplying in excess -1.5 A over a -1.2 to -37 V output voltage range. |
The LM237 and LM337 are adjustable 3-terminal negative-voltage regulators capable of supplying in excess of –1.5 A over an output voltage range of –1.2 V to –37 V. They require only two external resistors to set the output voltage and one output capacitor for frequency compensation.
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The LM337 serves a wide variety of applications including local, on card regulation. This device can also be used to make a programmable output regulator, or by connecting a fixed resistor between the adjustment and output, the LM337 can be used as a precision current regulator.
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- What are specifications of LM317 and LM337?
The LM237 and LM337 are adjustable 3-terminal negative-voltage regulators capable of supplying in excess of –1.5 A over an output voltage range of –1.2 V to –37 V. They require only two external resistors to set the output voltage and one output capacitor for frequency compensation.
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