RT9193-18GB 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). Requires a 1uF X7R input capacitor to GND for stability.
2	GND	power_in	Device ground reference. Common return for VIN, VOUT, EN and BP.
3	EN	input	Chip Enable, active high (TTL logic). VIH >= 1.2V enables the regulator; VIL <= 0.4V shuts it down. Input is high impedance (bias current ~0/100nA max), so a ~100kOhm pull-down to GND is recommended when the control signal is floating. Input range 0V to 5.5V.
4	BP	passive	Reference noise bypass pin. May be left floating; for lowest output noise (~100 uVrms, 10Hz-100kHz) connect a 22nF ceramic capacitor between BP and GND.
5	VOUT	power_out	Regulated output voltage, 1.8V nominal (-18 suffix), 300mA max load. Requires a 1uF X7R output capacitor to GND for stability. Current-limited (typ 400mA) and thermally protected (Tsd ~165 degC).

Key specifications

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

Ordering variants

Same part, different packaging or reel option.

RT9193-18GBB
RT9193-18GBU5
RT9193-18GBJ5
RT9193-18GBQW
RT9193-18GBF

CAD (KiCad official)

Symbol: RT9193-18GB
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
`rt9193-18gb.step`	85 KB	You want the bare part, or you mark your own boards.
`rt9193-18gb-etched.step`	2.2 MB	You want the part with `RT9193-18GB` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 538 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 f6c77df0675f253b, 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