MC78M12BDTRKG from onsemi, in a DPAK-3. 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	VI	power_in	Unregulated positive input voltage. Recommended operating input for 12 V variant is 14.5 V to 30 V; absolute maximum input is 35 V (V_I ≤ 18 V rated devices) with the 12 V part characterized at V_I = 19 V. A 0.33 µF input bypass capacitor to ground is recommended when the regulator is located far from the supply filter.
2	GND	power_in	Common ground reference for both the input and output. On the DPAK-3 (DT suffix) package the heatsink tab (terminal 4) is internally connected to Pin 2, so the thermal pad is at ground potential and may be soldered directly to a ground copper pour for heat dissipation.
3	VO	power_out	Regulated +12 V output. Typical V_O = 12 V (11.50 V min / 12.50 V max at T_J = 25 °C for the B-grade). Maximum output current with adequate heatsinking is 500 mA; short-circuit current limit is typically 350 mA and peak output current typically 700 mA. A 0.1 µF output capacitor to ground is recommended to improve transient response.

Key specifications

Parameter	Value
Manufacturer	onsemi
Package	DPAK-3
Category	PMIC
Pins	3

Ordering variants

Same part, different packaging or reel option.

MC78M12BDTRKG
MC78M12BDTRKGT
MC78M12BDTRKGTG

CAD (KiCad official)

Symbol: MC78M12BDTRKG
Footprint: Package_TO_SOT_SMD:TO-252-2
3D model: DPAK-3 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`mc78m12bdtrkg.step`	119 KB	You want the bare part, or you mark your own boards.
`mc78m12bdtrkg-etched.step`	2.0 MB	You want the part with `MC78M12BDTRKG` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 536 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: onsemi datasheet (15 pp, sha256 2339bbc0a38dcd3b, 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