RT9193-28GB from Richtek Tech, 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	Power input voltage. Operating range 2.5V to 5.5V (absolute max 6V). Bypass with a 1uF ceramic (X7R) capacitor to GND close to the pin.
2	GND	power_in	Ground reference for the regulator. Must be connected to system ground.
3	EN	input	Chip Enable (Active High). High-impedance TTL-compatible input; VIH >= 1.2V enables, VIL <= 0.4V shuts down (IBSD ~0-100nA). A 100kOhm pull-down to GND is recommended when the driving signal may float. EN input range 0V to 5.5V.
4	BP	passive	Reference Noise Bypass. May be left floating; for lowest output noise (typ 100uVRMS, 10Hz-100kHz) connect a 22nF capacitor from BP to GND.
5	VOUT	power_out	Regulated output voltage. Fixed 2.8V (RT9193-28 option) at up to 300mA with 220mV dropout. Requires a 1uF ceramic (X7R) output capacitor for stability; current-limited to typ 400mA with thermal shutdown at 165degC.

Key specifications

Parameter	Value
Manufacturer	Richtek Tech
Package	SOT-23-5
Category	PMIC
Pins	5

Ordering variants

Same part, different packaging or reel option.

RT9193-28GBB
RT9193-28GBU5
RT9193-28GBJ5
RT9193-28GBQW
RT9193-28GBF

CAD (KiCad official)

Symbol: RT9193-28GB
Footprint: Package_TO_SOT_SMD:SOT-23-5
3D model: SOT-23-5 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`rt9193-28gb.step`	85 KB	You want the bare part, or you mark your own boards.
`rt9193-28gb-etched.step`	2.4 MB	You want the part with `RT9193-28GB` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 558 faces against 102 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: Richtek Tech datasheet (14 pp, sha256 b14e82017ba100e6, 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