BL1117-50CY from BL Shanghai Belling, 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	GND	power_in	Ground reference for the regulator. Also serves as the thermal return via the DPAK tab (electrically connected to GND / tab).
2	Vout	power_out	Regulated 5.0V output, up to 1A load current. Requires a 10uF tantalum or MLCC output capacitor for stability (ESR 3mΩ~22Ω).
3	Vin	power_in	Unregulated input supply. Must be at least Vout+1.3V (dropout at 1A) up to 12V max operating (15V abs max). A 10uF input bypass capacitor is recommended.
TAB	GND	power_in	TO-252 (DPAK) exposed heat-slug tab, internally connected to the GND pin. Solder to a ground copper pour for heat dissipation; θJC = 10°C/W for TO-252.

Key specifications

Parameter	Value
Manufacturer	BL Shanghai Belling
Package	TO-252-2(DPAK)
Category	PMIC
Pins	4

Ordering variants

Same part, different packaging or reel option.

BL1117-50CYY
BL1117-50CY
BL1117-50CY50AY
BL1117-50CYX
BL1117-50CY50CX
BL1117-50CY50AX

CAD (KiCad official)

Symbol: BL1117-50CY
Footprint: Package_TO_SOT_SMD:TO-252-2
3D model: TO-252-2(DPAK) (KiCad packages3D, STEP)

Provenance

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

Datasheet: BL Shanghai Belling datasheet (15 pp, sha256 a7fe7f5c0846d4ca, 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