AL8861Y-13 from Diodes Incorporated, in a SOT-89-5. 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	LX	output	Drain of the internal 40V NDMOS switching MOSFET. Connect to the inductor/freewheel-diode node of the buck power stage. RDS(on) ~0.2Ω, peak inductor current limit 2A.
2	GND	power_in	Device ground (0V) reference for the internal regulator and control circuitry.
3	VSET	input	Multi-function on/off and brightness control input. Floats internally to ~4.5V via a 1.4µA source; drive <0.2V to shut down, 0.3-2.5V DC for 0-100% analog dimming (5-100% recommended), or apply PWM (f<500Hz, 1-100% duty) via an open-drain transistor. A capacitor to GND sets soft-start (default 0.1ms, ~1.5ms per nF). Absolute max 6V.
4	ISENSE	input	High-side current-sense input. Connect sense resistor RS between VIN and this pin to program the nominal average LED current: IOUT(NOM) = 0.1V / RS (100mV mean sense threshold, ±13% hysteresis).
5	VIN	power_in	Input supply, 4.5V to 40V (absolute max 42V). Decouple to GND with a ≥10µF X7R ceramic capacitor placed close to the device.

Key specifications

Parameter	Value
Manufacturer	Diodes Incorporated
Package	SOT-89-5
Category	LED-drv
Pins	5

Ordering variants

AL8861Y-13
AL8861Y-13WT-7
AL8861Y-13MP-13

CAD (KiCad official)

Symbol: AL8861Y-13
Footprint: Package_TO_SOT_SMD:SOT-89-5
3D model: SOT-89-5 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`al8861y-13.step`	86 KB	You want the bare part, or you mark your own boards.
`al8861y-13-etched.step`	1.6 MB	You want the part with `AL8861Y-13` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 402 faces against 26 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: Diodes Incorporated datasheet (18 pp, sha256 b1b15e2023cebf87, 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