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LM317 Regulator

The LM317 is an adjustable positive voltage regulator. Maximum output current, with adequate heatsinking is 1.5 A.

Recommended Operating Conditions

VOOutput voltage1.25 – 37V
VI – VOInput-to-output voltage differential3 – 40V
TjOperating junction temperature0 – 125°C
IO(MAX)Maximum output current1.5A

Voltage Regulator

LM317 typical schematic
Typical voltage regulator configuration.

The output voltage is calculated as

Output voltage

The ADJ terminal current IADJ is typically 50 µA, while the reference voltage VREF is 1.25 V.

0V to 30V Regulator

0V to 30V regulator
0V to 30V regulator.

The output voltage can be calculated as

0V to 30V regulator formula

High-Current Adjustable Regulator

High-current adjustable regulator
High-current adjustable regulator.

Transistors Q1 and Q2 allow higher output currents. The output voltage is determined by the resistors R1 and R2.

Useful link: LM317 datasheet (pdf).

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