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- LM117/LM317A/LM317
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- Other Electronics
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- Last added
- 2026-10-03
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National Semiconductor LM117/LM317A/LM317 Adjustable Regulator Datasheet
The LM117 series of adjustable 3‑terminal positive voltage regulators provides up to 1.5 A output over a 1.2 V to 37 V range. They require only two external resistors to set the output voltage and include built‑in current limit, thermal overload and safe‑area protection. The devices are offered in a variety of TO‑3, TO‑220, TO‑263, SOT‑223, TO‑39, TO‑252 and LCC packages.
The datasheet details absolute maximum ratings, electrical characteristics, typical performance curves and application hints such as recommended input and output capacitors, ripple‑rejection techniques, and heatsink calculations. Ordering information and package markings are also provided.
National Semiconductor LM117/LM317A/LM317 specifications
| Maximum output current | 1.5 A |
|---|---|
| Line regulation (LM317A) | 0.01 %/V |
| Load regulation (LM117) | 0.3 % |
| Ripple rejection | 80 dB |
| Input‑output voltage differential (max) | +40 V |
| Operating temperature range (LM117) | -55 °C to +150 °C |
Source: National Semiconductor LM117/LM317A/LM317 Adjustable Regulator Datasheet
All National Semiconductor LM117/LM317A/LM317 documents by type
Ratings, dimensions and ordering codes, for selection and design work.
- National Semiconductor LM117/LM317A/LM317 Adjustable Regulator Datasheet 28 p
- National Semiconductor LM117/LM317A/LM317 Adjustable Regulator Datasheet 28 p
- National Semiconductor LM117/LM317A/LM317 3-Terminal Adjustable Regulator Data Sheet 26 p
- National Semiconductor LM117/LM317A/LM317 Datasheet 28 p
- National Semiconductor LM117/LM317A/LM317 Adjustable Regulator Datasheet 26 p
Questions answered in these manuals
What input bypass capacitor is recommended for the LM117?
A 0.1 µF disc or 1 µF solid‑tantalum capacitor on the input is suitable for most applications.
From: National Semiconductor LM117/LM317A/LM317 Adjustable Regulator Datasheet
When is a heatsink required for the LM317 series?
A heatsink may be needed if the calculated thermal resistance exceeds the package rating, based on power dissipation and ambient temperature.
From: National Semiconductor LM117/LM317A/LM317 Adjustable Regulator Datasheet
How much ripple rejection can be achieved with the LM117?
The LM117 can achieve up to 80 dB ripple rejection when a 10 µF bypass capacitor is used on the adjustment terminal.
From: National Semiconductor LM117/LM317A/LM317 Adjustable Regulator Datasheet
What are the line‑regulation specifications for the LM317A?
The LM317A provides a line regulation of 0.01 % per volt.
From: National Semiconductor LM117/LM317A/LM317 Adjustable Regulator Datasheet
What is the maximum output current of the LM117 series?
The LM117 series can deliver up to 1.5 A of output current.
From: National Semiconductor LM117/LM317A/LM317 3-Terminal Adjustable Regulator Data Sheet
Are output capacitors required for the LM117?
No output capacitors are needed unless the device is more than 6 inches from the input filter capacitors, in which case an input bypass capacitor is recommended.
From: National Semiconductor LM117/LM317A/LM317 3-Terminal Adjustable Regulator Data Sheet