# SMAJ18A

**hongjiacheng** · ESD And Surge Protection (TVS/ESD) · DO-214AC(SMA)

SMAJ18A from hongjiacheng, in a DO-214AC(SMA). Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

## Pinout

| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | K | passive | Cathode terminal of the unidirectional SMAJ18A, marked by the cathode band on the package, and connected to the protected line (VRWM 18V, VBR 20 to 22.1V at 1mA, VC 29.2V at 13.7A IPP). |
| 2 | A | passive | Anode terminal of the unidirectional SMAJ18A, the end opposite the cathode band, and normally connected to ground (400W peak pulse power at 10/1000µs). |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | hongjiacheng |
| Package | DO-214AC(SMA) |
| Category | Circuit Protection |
| Pins | 2 |

## CAD (KiCad official)

- Symbol: `SMAJ18A`
- Footprint: `Diode_SMD:D_SMA`
- 3D model: DO-214AC(SMA) (KiCad packages3D, STEP)
- 3D model files: `smaj18a-etched.step` / `smaj18a-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `smaj18a.step` / `smaj18a.glb` are the bare package body.

## Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

- **Datasheet:** [hongjiacheng datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8786200048271077376) (5 pp, sha256 `3ff5a7b8618e9ea1`, retrieved 2026-10-12, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-sonnet-5-5` (text+vision), consensus `claude-opus-5-5` (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
- **CAD:** KiCad official libraries (CC-BY-SA 4.0).

[Datasheet PDF](docs/smaj18a-datasheet.pdf)