# SMF250A

**Changjing** · TVS · SOD-123FL

SMF250A from Changjing, in a SOD-123FL. 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 (marked with the cathode band) of the unidirectional TVS; reverse stand-off voltage VRWM 250V, breakdown 279-309V at 1mA, max clamping 405V at 0.5A IPP. |
| 2 | A | passive | Anode of the unidirectional TVS, opposite the cathode band; 200W peak power with a 10/1000us waveform. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Changjing |
| Package | SOD-123FL |
| Category | TVS/Fuse/Board Level Protection |
| Pins | 2 |

## Electrical characteristics

Limits as printed in the datasheet (page.json `metadata.characteristics` carries them as data).

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Reverse stand-off voltage | VRWM |  | 250 |  | V |  | 2 |
| Breakdown voltage | VBR | 279 |  | 309 | V | @IT = 1 mA | 2 |
| Maximum clamping voltage | VC |  |  | 405 | V | @IPP = 0.5 A | 2 |
| Maximum peak pulse current | IPP |  |  | 0.5 | A |  | 2 |
| Maximum reverse leakage | IR |  |  | 1 | uA | @VRWM | 2 |
| Peak power dissipation | PPPM |  |  | 200 | W | with a 10/1000us waveform | 1 |
| Operating junction and storage temperature range | TJ,TSTG | -55 |  | 150 | ℃ |  | 1 |
| Thermal resistance junction to lead | RθJL |  |  | 26 | ℃/W | Between junction and lead | 1 |
| Thermal resistance junction to ambient | RθJA |  |  | 300 | ℃/W | Between junction and Ambient | 1 |
| Test current | IT |  | 1 |  | mA | VBR test current | 2 |

## CAD (KiCad official)

- Symbol: `SMF250A`
- Footprint: `Diode_SMD:D_SOD-123F`
- 3D model: SOD-123FL (KiCad packages3D, STEP)
- 3D model files: `smf250a-etched.step` / `smf250a-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `smf250a.step` / `smf250a.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Changjing datasheet](docs/smf250a-datasheet.pdf) (5 pp, sha256 `150c24d4249959f9`, retrieved 2026-10-22, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-sonnet-5-5` (text), consensus `claude-sonnet-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/smf250a-datasheet.pdf)