LM2575S-3.3 from UMW, in a TO-263-5. 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	VIN	power_in	Input supply voltage. Operating range 4.75V to 40V for the LM2575 (up to 60V for the HV variant); absolute max 45V (LM2575) / 63V (LM2575HV). Requires a bulk input capacitor (e.g. 680 uF) close to this pin.
2	Output	output	Switching output from the internal 2A power transistor. Connects to the catch diode (e.g. 1N5824 Schottky) cathode and the output filter inductor. Saturation voltage ~1.16V at 2A; internal current limit typ. 2.2A.
3	GND	power_in	Device ground return. Also the thermal path for the TO-263 tab; the exposed tab is electrically connected to GND and should be soldered to a copper pour for heatsinking (theta_JA ~20-50 C/W depending on copper area).
4	Feedback	input	Output voltage feedback sense. On the fixed 3.3V version this pin is tied directly to the regulated output node; the internal reference regulates it to 3.3V (Vout tolerance +/-4% over line/load). Feedback bias current 10 nA typ (adjustable variant).
5	ON/OFF	input	Active-low shutdown input. Regulator is ON when the pin is low or left floating (VIL max 1.2V) and enters low-power standby when driven high (VIH min 1.4V, IQ_standby ~50 uA). Input range -0.3V to +VIN; TTL-compatible.

Key specifications

Parameter	Value
Manufacturer	UMW
Package	TO-263-5
Category	PMIC
Pins	5

Ordering variants

Same part, different packaging or reel option.

LM2575S-3.3
LM2575HVS-3.3
LM2575T-3.3
LM2575HVT-3.3

CAD (KiCad official)

Symbol: LM2575S-3.3
Footprint: Package_TO_SOT_SMD:TO-263-5_TabPin6
3D model: TO-263-5 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`lm2575s-3-3.step`	180 KB	You want the bare part, or you mark your own boards.
`lm2575s-3-3-etched.step`	2.0 MB	You want the part with `LM2575S-3.3` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 539 faces against 135 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: UMW datasheet (30 pp, sha256 b0c31af439f0b6b9, 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