BL8503-33PRM from BL Shanghai Belling, in a SOT-23-3L. 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	Vss	power_in	Ground reference for the regulator. Connect to system ground; place the 1 µF output capacitor return here.
2	Vout	power_out	Regulated 3.3V output (3.234-3.366 V, ±2%). Supplies up to 250 mA. Requires a 1 µF (tantalum recommended) output capacitor to ground for stability.
3	Vin	power_in	Unregulated supply input. Operating range 1.5 V to 8 V (absolute max 10 V). Requires a 1 µF (tantalum recommended) input capacitor to ground.

Key specifications

Parameter	Value
Manufacturer	BL Shanghai Belling
Package	SOT-23-3L
Category	PMIC
Pins	3

Ordering variants

BL8503-33PRM
BL8503-33PRMPSM
BL8503-33PRMPSA
BL8503-33PRMPSB
BL8503-33PRMPT

CAD (KiCad official)

Symbol: BL8503-33PRM
Footprint: Package_TO_SOT_SMD:SOT-23-3
3D model: SOT-23-3L (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`bl8503-33prm.step`	59 KB	You want the bare part, or you mark your own boards.
`bl8503-33prm-etched.step`	2.6 MB	You want the part with `BL8503-33PRM` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 598 faces against 69 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: BL Shanghai Belling datasheet (13 pp, sha256 8f6684221c2cf4c4, 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