Product Overview
National Semiconductor LM317T - adjustable positive regulator, TO-220
Condition
New. The photo shows a representative unit from our stock. Same or next business day shipping from our Idaho warehouse. Honest pricing, no nonsense. Online since 1999. We are here for our customers, with a no-hassle satisfaction guarantee.
Product Overview
The photographed body carries a two-line mark: the National Semiconductor logo followed by 51JR on the top line, LM317T P+ below it, with a bright metal mounting tab drilled for a screw and three straight leads. The LM317 is the standard three-terminal adjustable positive regulator, where two external resistors between the output and adjust pins set the output voltage. We have 76 of these on the shelf and they are sold each.
Key Features
- Adjustable positive output, 1.25 V to 37 V, per Texas Instruments' published LM317 data (SLVS044)
- Output current 1.5 A maximum, correct for this TO-220 body, per TI's published LM317 data
- Internal reference 1.25 V nominal between the output and adjust pins, per TI's published LM317 data
- About 3 V of input-to-output headroom for full performance; 40 V maximum differential, per TI's published LM317 data
- Line regulation 0.01 %/V typical, load regulation 0.1 % typical, per TI's published LM317 data
- Operating junction temperature 0 C to 125 C for the LM317 grade, per TI's published LM317 data
- Package: TO-220, three leads, the T suffix in the part number; the photographed body is marked LM317T P+
- Floating two-terminal operation for high-voltage rails is described in TI's published LM317 data
Verify against Texas Instruments' published LM317 data before designing in.
Applications
- Setting a bench supply rail with a pot or a resistor pair
- Dropping a higher rail to a value no fixed regulator offers
- Simple constant-current sources using the 1.25 V reference across one resistor
- Repairing older linear supplies that used a three-terminal adjustable regulator
Frequently Asked Questions
How many should I order? Order the count your build needs; we hold 76 on the shelf, so a handful for a build plus a couple of spares is no problem. Shipping is $8 flat rate and free on orders over $28, so small parts like this ship smartest as part of a larger order.
What exactly is printed on the part? Two lines: the maker's logo with 51JR beside it, and LM317T P+ underneath. We quote 51JR as it reads and do not decode it. LM317T is the orderable TO-220 part number; a bare LM317 is the family name.
The company whose logo is on this case was folded into another one years ago, and the part number printed under it has outlived the nameplate.
