AZ431AN-ATRG1-MS from MSKSEMI, in a SOT-23. 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	REF	input	Reference input. Internally compared to the 2.5V bandgap reference (Vref = 2.475-2.525V). Reference input current typ 1.5µA. Connected to the external resistor divider that sets Vout = Vref(1+R1/R2)+R1Iref.
2	K	passive	Cathode. Shunt regulator cathode terminal; sinks the regulated current. Max cathode voltage 36V; continuous cathode current range -100 to +150mA. Minimum cathode current for regulation ~0.45mA.
3	A	passive	Anode. Common return terminal for the shunt regulator; typically tied to circuit ground/low side of the resistor divider.

Key specifications

Parameter	Value
Manufacturer	MSKSEMI
Package	SOT-23
Category	PMIC
Pins	3

Ordering variants

AZ431AN-ATRG1-MS

CAD (KiCad official)

Symbol: AZ431AN-ATRG1-MS
Footprint: Package_TO_SOT_SMD:SOT-23
3D model: SOT-23 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`az431an-atrg1-ms.step`	59 KB	You want the bare part, or you mark your own boards.
`az431an-atrg1-ms-etched.step`	2.0 MB	You want the part with `AZ431AN-ATRG1-MS` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 524 faces against 69 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 (7 pp, sha256 a2a785a6ee5ee4aa, 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