LD1117AS33TR from STMicroelectronics, in a SOT-223-4. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin	Name	Type	Function
1	ADJ/GND	power_in	Ground reference pin for the fixed 3.3 V version (labeled ADJ/GND because the same die is used for the adjustable variant). Tie directly to system ground for the LD1117AS33TR. Quiescent current is typically 5 mA.
2	VOUT	power_out	Regulated 3.3 V output (typ 3.3 V, 3.234-3.366 V at 25 °C, 10 mA). Sources up to 1 A (min 1000 mA, typ 1200 mA short-circuit). Requires a ≥10 µF output capacitor for loop stability. Internally connected to the exposed metal tab.
3	VIN	power_in	Unregulated DC input supply. Operating input voltage up to 10 V (absolute max 15 V). Minimum VIN for 3.3 V regulation is ~4.75 V (dropout typ 1.15 V at 1 A). A 100 nF input decoupling capacitor is recommended.
4	TAB	power_out	Large SOT-223 heat-sink tab, internally shorted to VOUT. Provides the primary thermal path (RthJC = 15 °C/W); should be soldered to a copper area on the PCB that is also the VOUT net.

Key specifications

Parameter	Value
Manufacturer	STMicroelectronics
Package	SOT-223-4
Category	PMIC
Pins	4

Ordering variants

Same part, different packaging or reel option.

LD1117AS33TR
LD1117AS33TRASTR
LD1117AS33TRAS12TR
LD1117AS33TRAS18TR
LD1117AS33TRADT33TR
LD1117AS33TRADT-TR
LD1117AS33TRADT12TR
LD1117AS33TRADT18TR
LD1117AS33TRAV33

CAD (KiCad official)

Symbol: LD1117AS33TR
Footprint: Package_TO_SOT_SMD:SOT-223
3D model: SOT-223-4 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`ld1117as33tr.step`	64 KB	You want the bare part, or you mark your own boards.
`ld1117as33tr-etched.step`	1.9 MB	You want the part with `LD1117AS33TR` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 482 faces against 75 in the bare model. It survives export, section views, and rendering in any CAD tool, and it drops straight into KiCad or Fusion with no extra setup.

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

Datasheet: STMicroelectronics datasheet (24 pp, sha256 c2dd41daa75f2827, retrieved 2026-08-17, tier: manufacturer)
Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF