SE8550K2-HF from Seaward Elec, in a SOT-89-3. 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	GND	power_in	Device ground reference. Connect to system ground with a low-impedance return path; input and output decoupling capacitor returns should terminate here.
2	VIN	power_in	Power supply input. Operating range VOUT+1 V to 35 V (absolute max 40 V). Requires a 1 µF ceramic input capacitor placed close to the pin.
3	VOUT	power_out	Regulated output voltage (5.0 V fixed for this SKU), rated ≥200 mA with typical 600 mV dropout at 200 mA. Requires a ≥1 µF (10 µF recommended) ceramic output capacitor placed close to the pin.

Key specifications

Parameter	Value
Manufacturer	Seaward Elec
Package	SOT-89-3
Category	PMIC
Pins	3

Ordering variants

Same part, different packaging or reel option.

SE8550K2-HF
SE8550K1-HF
SE8550X1-HF
SE8550X2-HF
SE8550L1-HF
SE8550L2-HF

CAD (KiCad official)

Symbol: SE8550K2-HF
Footprint: Package_TO_SOT_SMD:SOT-89-3
3D model: SOT-89-3 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`se8550k2-hf.step`	57 KB	You want the bare part, or you mark your own boards.
`se8550k2-hf-etched.step`	1.8 MB	You want the part with `SE8550K2-HF` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 452 faces against 42 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: Seaward Elec datasheet (10 pp, sha256 0cbe3738392b321a, retrieved 2026-08-17, tier: lcsc)
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