MIC39100-3.3WS-TR from Microchip, in a SOT-223. 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	IN	power_in	Unregulated supply input. Operating range +2.25V to +16V (absolute max -20V to +20V). Requires an input capacitor for stability; withstands reversed-battery and reversed-leakage conditions.
2	GND	power_in	Device ground/return. Ground pin current (IGND) is typically 11 mA at IOUT = 1A. This pin is electrically common with the SOT-223 tab.
3	OUT	power_out	Regulated 3.3V output at up to 1A minimum guaranteed. 1% initial accuracy; requires a 10 µF tantalum (or equivalent) output capacitor for stability. Current-limited to typically 1.8A and thermally protected.
TAB	GND	power_in	SOT-223 heatsink tab, internally connected to GND (pin 2). Solder to a copper pour for thermal dissipation; θJC = 15 °C/W.

Key specifications

Parameter	Value
Manufacturer	Microchip
Package	SOT-223
Category	PMIC
Pins	4

Ordering variants

Same part, different packaging or reel option.

MIC39100-3.3WS-TR
MIC39100-3.3WS-TRS
MIC39100-3.3WS-TRM

CAD (KiCad official)

Symbol: MIC39100-3.3WS-TR
Footprint: Package_TO_SOT_SMD:SOT-223-3_TabPin2
3D model: SOT-223 (KiCad packages3D, STEP)

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

Datasheet: Microchip datasheet (24 pp, sha256 f165c1e273f27a4b, 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