# SMF350A

**YFW** · Electrostatic And Surge Protection (TVS/ESD) · SOD-123FL

SMF350A from YFW, 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 | Cathode | passive | Cathode of the unipolar SMF350A TVS diode, with 350 V working peak reverse voltage, 391 V to 432 V breakdown at 1 mA, and 567 V max clamping voltage at 0.4 A peak pulse current. |
| 2 | Anode | passive | Anode of the unipolar SMF350A TVS diode, rated for 200 W peak pulse power (10/1000 us) and 1 uA max reverse leakage at VRWM. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | YFW |
| 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 (working peak reverse) voltage | VRWM |  | 350 |  | V |  | 2 |
| Breakdown voltage | VBR | 391 |  | 432 | V | @ IT | 2 |
| Breakdown test current | IT |  | 1 |  | mA |  | 2 |
| Reverse leakage current | IR |  |  | 1 | μA | @ VRWM | 2 |
| Maximum clamping voltage | VC |  |  | 567 | V | @ IPP | 2 |
| Peak pulse current | IPP |  |  | 0.4 | A |  | 2 |
| Peak pulse power dissipation | PPPM |  |  | 200 | W | TA=25°C, 10/1000us waveform | 1 |
| Peak forward surge current | IFSM |  |  | 20 | A | 8.3ms single half sinewave (UNI) | 1 |
| Steady state power dissipation | PM(AV) |  |  | 1 | W | lead temperature TL=75°C | 1 |
| Operating junction and storage temperature range | TJ,TSTG | -55 |  | 150 | °C |  | 1 |
| Typical thermal resistance | RθJA |  | 180 |  | °C/W |  | 1 |

## Materials and finish

As the datasheet states them (page.json `metadata.appearance`; the 3D model's colours follow it).

| Part | Material | Colour / plating | Datasheet says | Page |
|---|---|---|---|---|
| contacts | copper |  | 2. Mounted on 5mm2 copper pads to each terminal | 1 |

## CAD (KiCad official)

- Symbol: `SMF350A`
- Footprint: `Diode_SMD:D_SOD-123F`
- 3D model: SOD-123FL (KiCad packages3D, STEP)
- 3D model files: `smf350a-etched.step` / `smf350a-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `smf350a.step` / `smf350a.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [YFW datasheet](docs/smf350a-datasheet.pdf) (4 pp, sha256 `e622291b3f700ab4`, 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/smf350a-datasheet.pdf)