L78M12CDT-TR from STMicroelectronics, in a TO-252-2(DPAK). 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	INPUT	power_in	Unregulated positive DC input. Absolute maximum 35 V for 5-18 V output versions (40 V for 20/24 V versions). Bypass to GND with ~0.33 uF ceramic close to the pin for stability and transient rejection.
2	GND	power_in	Common ground reference for input and output. Electrically connected to the DPAK tab (heatsink); the tab must be soldered to a copper pour that acts as both the ground return and the primary heat-dissipation path (RthJA ~= 100 C/W without additional heatsinking).
3	OUTPUT	power_out	Regulated +12 V output, 500 mA nominal (internally current-limited). Requires a 0.1 uF ceramic bypass close to the pin to ensure loop stability and transient response.

Key specifications

Parameter	Value
Manufacturer	STMicroelectronics
Package	TO-252-2(DPAK)
Category	PMIC
Pins	3

Ordering variants

Same part, different packaging or reel option.

L78M12CDT-TR
L78M12CDT-TRCV
L78M12CDT-TRABV
L78M12CDT-TRCH

CAD (KiCad official)

Symbol: L78M12CDT-TR
Footprint: Package_TO_SOT_SMD:TO-252-2
3D model: TO-252-2(DPAK) (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`l78m12cdt-tr.step`	119 KB	You want the bare part, or you mark your own boards.
`l78m12cdt-tr-etched.step`	1.6 MB	You want the part with `L78M12CDT-TR` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 436 faces against 83 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 (46 pp, sha256 bf25de1549fb4045, 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