AZ431AR-ATRE1 from Diodes Incorporated, in a SOT-89-3. 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 (feedback) input. Compared internally to the 2.5 V bandgap; when REF exceeds VREF the internal transistor sinks current from cathode to anode. Max reference input current 10 mA absolute, typ input bias 0.7 µA.
2	CATHODE	passive	Shunt cathode (K). Sinks the regulation current when REF rises above VREF. Operating cathode voltage VREF to 36 V, cathode current 1 mA to 100 mA (absolute max -100 to 150 mA), off-state leakage 0.05 µA typ.
3	ANODE	passive	Shunt anode (A), the common return for the reference and the shunt transistor. Normally tied to the low side of the regulated node (circuit ground in a standard shunt-regulator topology).

Key specifications

Parameter	Value
Manufacturer	Diodes Incorporated
Package	SOT-89-3
Category	PMIC
Pins	3

Ordering variants

AZ431AR-ATRE1
AZ431AR-ATRE1R
AZ431AR-ATRE1Z
AZ431AR-ATRE1N

CAD (KiCad official)

Symbol: AZ431AR-ATRE1
Footprint: Package_TO_SOT_SMD:SOT-89-3
3D model: SOT-89-3 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`az431ar-atre1.step`	57 KB	You want the bare part, or you mark your own boards.
`az431ar-atre1-etched.step`	1.4 MB	You want the part with `AZ431AR-ATRE1` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 403 faces against 42 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 (19 pp, sha256 af7f4848d81a3997, 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