BL8558-28PRN from BL Shanghai Belling, in a SOT-23-5. 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	Vin	power_in	Regulator input supply. Accepts up to 8V (recommended), 10V absolute max. Bypass with 1uF ceramic capacitor to GND close to the pin.
2	Vss	power_in	Ground / common return for the regulator.
3	CE	input	Chip Enable input. Drive high (Vceh >= 1.5V, up to Vin) to enable regulator; drive low (Vcel <= 0.25V) to enter standby (Istandby = 0.1uA typ). Internal pull-down resistor to GND (Rpd = 2-10 MOhm, 5 MOhm typ).
4	NC	unconnected	No internal connection. Leave floating or tie to GND per PCB preference.
5	Vout	power_out	Regulated output. Fixed 2.8V on BL8558-28PRN (±2%), 500mA max output current. Requires 3.3uF/4.7uF output capacitor for stability.

Key specifications

Parameter	Value
Manufacturer	BL Shanghai Belling
Package	SOT-23-5
Category	PMIC
Pins	5

Ordering variants

Same part, different packaging or reel option.

BL8558-28PRN
BL8558-28PRNPRC
BL8558-28PRNPSA
BL8558-28PRNPSB
BL8558-28PRNPRM
BL8558-28PRNPT

CAD (KiCad official)

Symbol: BL8558-28PRN
Footprint: Package_TO_SOT_SMD:SOT-23-5
3D model: SOT-23-5 (KiCad packages3D, STEP)

Provenance

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

Datasheet: BL Shanghai Belling datasheet (10 pp, sha256 e45fcf409b9d0231, 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