# BAS21

**Nexperia** · Diodes - General Purpose · SOT-23

BAS21 from Nexperia, in a SOT-23. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

## Pinout

| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | A | passive | Anode of the switching diode. Forward current flows from anode (pin 1) to cathode (pin 3); VF ≤ 1 V at IF = 100 mA. |
| 2 | NC | unconnected | Not connected. No internal bond; leave floating or tie to any convenient net. |
| 3 | K | passive | Cathode of the switching diode. Reverse voltage rating VR = 200 V (VRRM = 250 V); reverse current ≤ 100 nA at VR = 200 V, Tj = 25 °C. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Nexperia |
| Package | SOT-23 |
| Category | Diodes |
| Pins | 3 |

## CAD (KiCad official)

- Symbol: `BAS21`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `bas21-etched.step` / `bas21-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `bas21.step` / `bas21.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Nexperia datasheet](https://assets.nexperia.com/documents/data-sheet/BAS21.pdf) (10 pp, sha256 `4632cdc90d8753d1`, retrieved 2026-08-17, tier: manufacturer)
- **Extractor:** `ds2sf` (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
- **CAD:** KiCad official libraries (CC-BY-SA 4.0).

[Datasheet PDF](docs/bas21-datasheet.pdf)