LM317KTTR is a Texas Instruments LM317 1.5 A adjustable linear regulator in 3-pin TO-263 (DDPAK), 500-piece tape and reel — 1.25 V to 37 V output set by two resistors, 0.01%/V line regulation and 0.1% load regulation typical, internal current limiting, thermal overload and safe-operating-area protection that stays functional even with the ADJUST pin disconnected. The KTTR code is the selection point: the SMD TO-263 version on reel for pick-and-place assembly — the same LM317 die as the TO-220 (KCS/KCT) through-hole versions, but for reflow production. Selection advice: pick the linear LM317 when the dropout budget allows it and you want the simplest possible adjustable rail — two resistors, no inductor, no layout risk. For high step-down ratios at 1.5 A, a switching regulator wastes far less heat; the dropout of the LM317 (≈2–3 V typical) times load current is the heat you must sink. The 500-piece reel suits production; prototypes use the tube TO-220 codes. Evidence: TI LM317 product page and datasheet package addendum confirm KTT = 3-pin TO-263, 500-piece reel, 1.5 A and 1.25–37 V. Match the full LM317KTTR code.
Ordering-code highlights reviewed against official manufacturer documentation.
LM317 is available in the following manufacturer order codes. They share the same Adjustable linear regulator design; the table highlights package, packing and ordering differences. Quote the exact code your BOM needs.
| Order code | Package | Packing | Key difference |
|---|---|---|---|
| LM317DCY | SOT-223-4 | Tube | SOT-223, tube |
| LM317DCYR | SOT-223-4 | Tape and reel | SOT-223, tape and reel |
| LM317KTTR | TO-263-3 | LARGE T&R | Package/pins: TO-263 (KTT), 3 pins; LM317DCY is SOT-223 (DCY), 4 pins; do not assume direct replacement — verify PCB pads, thermal and pinout; factory packing is LARGE T&R, 500 per pack; LM317DCY is TUBE, 80 per pack. |
| LM317T/NOPB | TO-220-3 | — | TO-220 through-hole package |
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Browse existing catalog records — same series first, then the same category and manufacturer. These are not confirmed replacements; compatibility requires engineering review.
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These are order-code variants of the same Texas Instruments series. They share the core design; the ordering code selects the exact configuration — LM317DCY: SOT-223, tube; LM317DCYR: SOT-223, tape and reel; LM317T/NOPB: TO-220 through-hole package. LM317KTTR itself is the TO-263-3 configuration. A code that differs by even one character may be a different device, so always quote the complete code exactly as it appears on your BOM.
From the verified technical profile: Package code: TO-263 (KTT); Pin count: 3; Operating temperature: 0 to 125 °C. These are the catalog-recorded values for LM317KTTR — always re-check them against the manufacturer datasheet revision quoted on your BOM before finalizing the design.