H9108 from Shanghai Siproin Microelectronics, in a SOT-23-6. 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	BS	passive	Bootstrap pin for the high-side N-MOSFET gate driver. A bootstrap capacitor (typically 22nF ceramic) is connected between BS and SW to form a floating supply that boosts the high-side switch gate above VIN.
2	GND	power_in	Device ground reference. Should be connected to a large copper area for thermal dissipation and to serve as the return for the input capacitor, output capacitor, and feedback divider.
3	FB	input	Feedback input to the error amplifier. Connect to the center tap of an external resistor divider from VOUT to GND; the regulator servos FB to the internal 0.6V reference (VOUT = 0.6V x (R1+R2)/R2).
4	EN	input	Enable input. Drive high (VENH >= 1.4V) to enable the converter; drive low (VENL <= 0.9V) to disable and enter micro-power shutdown (~4uA). Can be tied to VIN through a pull-up resistor (e.g. 100k) for auto-start.
5	IN	power_in	Power supply input, 4V to 18V (absolute max 18V, -0.3V min). Bypass with a low-ESR ceramic capacitor placed close to the pin (typ. 22uF).
6	SW	output	Switch node output. Common drain of the internal high-side and low-side MOSFETs; connect to the external inductor. Rated -0.3V to (VIN+0.5V); high-side RDS(on) ~100mOhm, low-side ~70mOhm.

Key specifications

Parameter	Value
Manufacturer	Shanghai Siproin Microelectronics
Package	SOT-23-6
Category	PMIC
Pins	6

CAD (KiCad official)

Symbol: H9108
Footprint: Package_TO_SOT_SMD:SOT-23-6
3D model: SOT-23-6 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`h9108.step`	97 KB	You want the bare part, or you mark your own boards.
`h9108-etched.step`	1.4 MB	You want the part with `H9108` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 332 faces against 117 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: Shanghai Siproin Microelectronics datasheet (10 pp, sha256 d888f77e06c51893, 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