# SMCJ43A

**Littelfuse** · ESD And Surge Protection (TVS/ESD) · DO-214AB

SMCJ43A from Littelfuse, in a DO-214AB. 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 (positive end) of the unidirectional SMCJ43A, marked by the color band; VR 43.0 V stand-off, VBR 47.8 to 52.8 V at 1 mA. |
| 2 | A | passive | Anode terminal of the unidirectional SMCJ43A, opposite the cathode band, with a maximum clamping voltage of 69.4 V at 21.7 A Ipp. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Littelfuse |
| Package | DO-214AB |
| Category | Circuit Protection |
| Pins | 2 |

## CAD (KiCad official)

- Symbol: `SMCJ43A`
- Footprint: `Diode_SMD:D_SMC`
- 3D model: DO-214AB (KiCad packages3D, STEP)
- 3D model files: `smcj43a-etched.step` / `smcj43a-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `smcj43a.step` / `smcj43a.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Littelfuse datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8590237150974545920) (6 pp, sha256 `29531c61c5717811`, retrieved 2026-10-13, 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/smcj43a-datasheet.pdf)