# BAS21SW

**YFW** · Switching Diodes · SOT-323

BAS21SW from YFW, in a SOT-323. 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 | A1 | passive | Anode of the first diode of the series pair in the BAS21SW dual high-voltage switching diode (BAS21W type: VR 250 V, IF(AV) 200 mA). |
| 2 | K2 | passive | Cathode of the second diode of the series pair in the BAS21SW dual high-voltage switching diode (VR 250 V, IF(AV) 200 mA per diode). |
| 3 | K1/A2 | passive | Common junction node between the cathode of the first diode and the anode of the second diode (series connection), shown as the top pin of the package. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | YFW |
| Package | SOT-323 |
| Category | Diodes |
| Pins | 3 |

## CAD (KiCad official)

- Symbol: `BAS21SW`
- Footprint: `Package_TO_SOT_SMD:SOT-323_SC-70`
- 3D model: SOT-323 (KiCad packages3D, STEP)
- 3D model files: `bas21sw-etched.step` / `bas21sw-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `bas21sw.step` / `bas21sw.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [YFW datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8603005437339971584) (3 pp, sha256 `93f6cc869491e66a`, retrieved 2026-10-18, 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/bas21sw-datasheet.pdf)