SY8303AAIC from Silergy Corp, in a TSOT-23-8. 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	FB	input	Output feedback pin. Connect to the center of the external output resistor divider to program VOUT = 0.6 * (1 + R1/R2). Internal reference is 0.6V (±1.5%).
2	FS	input	Switching frequency programming pin. Connect a resistor from this pin to ground; Fsw(kHz) = 1e5 / RFS(kΩ), giving a range of 500kHz to 2.5MHz (RFS = 40kΩ to 200kΩ).
3	GND	power_in	Device ground reference. Both GND pins (3 and 4) must be connected to the PCB ground plane.
4	GND	power_in	Device ground reference. Both GND pins (3 and 4) must be connected to the PCB ground plane. Pin 2 (per θJC note) is the case reference for thermal measurement; both GND pins carry return current.
5	IN	power_in	Power input pin. Operating range 4.5V to 40V (absolute max 40V vs GND). Decouple to GND with at least 4.7µF ceramic capacitor placed close to the pin.
6	LX	power_out	Switching node. Connect to one end of the external power inductor. Internal high-side (110 mΩ) and low-side (70 mΩ) FETs switch this node between IN and GND.
7	BS	power_in	Bootstrap pin for the internal high-side gate driver. Connect a 100nF ceramic capacitor between BS and LX. BS-LX absolute maximum is 4V.
8	EN	input	Enable control input. Pull high to turn on the regulator (VENH = 1.5V max threshold); pull low to shut down (VENL = 0.5V min threshold, IShdn ≈ 1µA). Do not float.

Key specifications

Parameter	Value
Manufacturer	Silergy Corp
Package	TSOT-23-8
Category	PMIC
Pins	8

Ordering variants

Same part, different packaging or reel option.

SY8303AAIC

CAD (KiCad official)

Symbol: SY8303AAIC
Footprint: Package_TO_SOT_SMD:SOT-23-8
3D model: TSOT-23-8 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`sy8303aaic.step`	123 KB	You want the bare part, or you mark your own boards.
`sy8303aaic-etched.step`	2.4 MB	You want the part with `SY8303AAIC` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 575 faces against 147 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 (6 pp, sha256 3a91281a9799f4d9, 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