PT4115-MS from MSKSEMI, in a SOT89-5. 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	SW	output	Switching output; drain of the internal high-side power MOSFET (RDS(on) ~450 mΩ). Connect to the LED / inductor node of the buck converter. Rated up to 1.2 A peak (IMAX).
2	VSS	power_in	Chip ground reference. Connect to system ground.
3	DIM	input	Brightness / dimming control input. Accepts a PWM signal (up to 20 kHz) or a DC analog level (0.5 V to 2.5 V) to set LED current. Pulling DIM below 0.3 V places the device in shutdown/standby. Internally pulled up (~500 kΩ) to an internal 5 V rail; max pin voltage 6 V.
4	CS	input	High-side current-sense input. Connects to the low side of the external sense resistor RCS between VIN and CS; the internal comparator regulates LED current so that VIN − VCS ≈ 100 mV (±3%). Input bias current ~10 µA.
5	VIN	power_in	Supply input, 5.5 V to 30 V (absolute max 35 V). Powers the internal 5 V regulator, control logic, and high-side MOSFET.

Key specifications

Parameter	Value
Manufacturer	MSKSEMI
Package	SOT89-5
Category	LED-drv
Pins	5

Ordering variants

Same part, different packaging or reel option.

PT4115-MS

CAD (KiCad official)

Symbol: PT4115-MS
Footprint: Package_TO_SOT_SMD:SOT-89-5
3D model: SOT89-5 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`pt4115-ms.step`	86 KB	You want the bare part, or you mark your own boards.
`pt4115-ms-etched.step`	1.2 MB	You want the part with `PT4115-MS` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 309 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: MSKSEMI datasheet (12 pp, sha256 bb150976b1f46900, retrieved 2026-08-17, tier: lcsc)
Datasheet language: Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
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