# CJ431D-N3A-ARG

**Changjing** · Voltage Regulators - Linear, Low Drop Out (LDO) Regulators · SOT-23

CJ431D-N3A-ARG from Changjing, 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 | R | input | Reference input pin. Compared internally to the 2.500 V bandgap reference; drive from the external divider between Cathode and Anode to program VKA. IREF is typically 0.7 uA (max 4 uA). |
| 2 | K | power_in | Cathode. Shunt current input / regulated output node. Sinks 1 mA to 100 mA of cathode current (IKA), absolute max VKA = 40 V, recommended max VKA = 36 V. Dynamic impedance ZKA typ 0.15 Ω. |
| 3 | A | power_in | Anode pin, normally grounded. All device voltages are referenced to the anode terminal. |

## Key specifications

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

## Ordering variants

Same part, different packaging or reel option.

- `CJ431D-N3A-ARG`
- `CJ431D-N3A-BRG`
- `CJ431D-N3A-ARGP3A-ARG`
- `CJ431D-N3A-ARGP3A-BRG`
- `CJ431D-N3A-ARGTAA-AAG`
- `CJ431D-N3A-ARGTAA-ABG`
- `CJ431D-N3A-ARGTAA-BAG`
- `CJ431D-N3A-ARGTAA-BBG`
- `CJ431D-N3A-ARGN3B-ARG`
- `CJ431D-N3A-ARGN3B-BRG`

## CAD (KiCad official)

- Symbol: `CJ431D-N3A-ARG`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `cj431d-n3a-arg-etched.step` / `cj431d-n3a-arg-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `cj431d-n3a-arg.step` / `cj431d-n3a-arg.glb` are the bare package body.

## 3D model downloads

Two STEP files. Same geometry, different body top:

| File | Size | Use it when |
|---|---|---|
| [`cj431d-n3a-arg.step`](cj431d-n3a-arg.step) | 59 KB | You want the bare part, or you mark your own boards. |
| [`cj431d-n3a-arg-etched.step`](cj431d-n3a-arg-etched.step) | 2.0 MB | You want the part with `CJ431D-N3A-ARG` already on it. |

The marking in the etched file is real recessed geometry cut into the solid, not a
texture or a decal: 509 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](docs/cj431d-n3a-arg-datasheet.pdf) (24 pp, sha256 `b75990ca44bd0e7d`, 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](docs/cj431d-n3a-arg-datasheet.pdf)