# BAS31

**Nexperia** · Avalanche Diodes · SOT-23

BAS31 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 first diode. Series path is A (pin 1) -> diode -> CC (pin 3) -> diode -> K (pin 2). VF max 1.25 V at IF = 400 mA (Tj = 25 C). |
| 2 | K | passive | Cathode of the second diode. Continuous reverse voltage max 90 V; repetitive peak reverse voltage max 110 V. |
| 3 | CC | passive | Common connection between the cathode of the first diode and the anode of the second diode, forming a series-connected double diode. Available as a shared node for the two switching diodes. |

## Key specifications

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

## Ordering variants

Same part, different packaging or reel option.

- `BAS31`

## CAD (KiCad official)

- Symbol: `BAS31`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `bas31-etched.step` / `bas31-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `bas31.step` / `bas31.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/BAS31.pdf) (9 pp, sha256 `09c8e51b0edffd81`, 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/bas31-datasheet.pdf)