CJ431 from Changjing, in a SOT-23. Pinout and pin descriptions extracted from the datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin	Name	Type	Function
1	REF	input	Reference input. Compared internally against the 2.5 V (typ.) bandgap reference; when REF exceeds Vref the device sinks current from cathode to anode. Reference input current is 1.5 µA typ. (4 µA max) with a 10 kΩ divider at IKA=10 mA.
2	A	power_in	Anode. Common/ground terminal of the shunt regulator; the low side of the programmable zener. Typically tied to circuit ground in shunt-regulator applications.
3	K	power_in	Cathode. High side of the programmable shunt; sinks the regulated current when the reference threshold is exceeded. Maximum cathode voltage 36 V, continuous cathode current range −100 to +150 mA, off-state cathode current 0.05 µA typ. (1 µA max) at VKA=36 V.

Key specifications

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

Ordering variants

Same part, different packaging or reel option.

CJ431 (marking '431')
CJ431CD431 (marking 'CD431')
CJ431 (SOT-89 reel, marking 'CJ431')
CJ431 (bulk)
CJ431-TA (tape)

CAD (KiCad official)

Symbol: CJ431
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
`cj431.step`	59 KB	You want the bare part, or you mark your own boards.
`cj431-etched.step`	1007 KB	You want the part with `CJ431` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 249 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: Changjing datasheet (9 pp, sha256 68a405075950c4b5, 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