SY8291ABC from Silergy Corp, 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	Boot-strap pin. Supplies the high-side gate driver via a bootstrap capacitor. Decouple to LX with a 0.1 µF (100 nF) ceramic cap. BS-to-LX voltage rating 3.6V absolute max (3.3V recommended).
2	GND	power_in	Device ground return. Also functions as the primary thermal path; maximize copper area for best thermal performance.
3	FB	input	Output feedback pin. Connect to the center of the R1/R2 resistor divider from VOUT to program the output: VOUT = 0.6 × (1 + R1/R2). Reference is 0.6V ±2%. FB absolute max 3.6V.
4	EN	input	Enable control input. Pull high to turn on the regulator; do not float. VENH ≈ 1.5V rising, VENL ≈ 0.4V falling. Absolute max EN voltage is VIN + 0.6V.
5	IN	power_in	Supply input pin. 5V to 40V operating range (42V absolute max). Decouple to GND with at least a 1 µF (4.7 µF recommended) low-ESR ceramic capacitor placed close to the pin.
6	LX	power_out	Inductor / switch node. Connect to the external inductor and the anode of the freewheeling Schottky diode. Internal N-channel power FET RDS(on) ≈ 180 mΩ; current limit ≈ 2A.

Key specifications

Parameter	Value
Manufacturer	Silergy Corp
Package	SOT-23-6
Category	PMIC
Pins	6

Ordering variants

Same part, different packaging or reel option.

SY8291ABC

CAD (KiCad official)

Symbol: SY8291ABC
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
`sy8291abc.step`	97 KB	You want the bare part, or you mark your own boards.
`sy8291abc-etched.step`	2.0 MB	You want the part with `SY8291ABC` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 481 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: Silergy Corp datasheet (9 pp, sha256 e4d186cfba2c4177, 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