# SI4401BDY

**TECH PUBLIC** · MOSFETs · SOP-8

SI4401BDY from TECH PUBLIC, in a SOP-8. 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 | S | passive | Source of the P-channel MOSFET, connected internally with pins 2 and 3. |
| 2 | S | passive | Source of the P-channel MOSFET, connected internally with pins 1 and 3. |
| 3 | S | passive | Source of the P-channel MOSFET, connected internally with pins 1 and 2. |
| 4 | G | input | Gate of the P-channel MOSFET; VGS rated ±20 V, threshold -1.0 V to -2.5 V. |
| 5 | D | passive | Drain of the P-channel MOSFET (VDS -40 V, ID -12 A), connected internally with pins 6, 7 and 8. |
| 6 | D | passive | Drain of the P-channel MOSFET (VDS -40 V, ID -12 A), connected internally with pins 5, 7 and 8. |
| 7 | D | passive | Drain of the P-channel MOSFET (VDS -40 V, ID -12 A), connected internally with pins 5, 6 and 8. |
| 8 | D | passive | Drain of the P-channel MOSFET (VDS -40 V, ID -12 A), connected internally with pins 5, 6 and 7. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | TECH PUBLIC |
| Package | SOP-8 |
| Category | Transistors/Thyristors |
| Pins | 8 |

## CAD (KiCad official)

- Symbol: `SI4401BDY`
- Footprint: `Package_SO:SOIC-8_3.9x4.9mm_P1.27mm`
- 3D model: SOP-8 (KiCad packages3D, STEP)
- 3D model files: `si4401bdy-etched.step` / `si4401bdy-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `si4401bdy.step` / `si4401bdy.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [TECH PUBLIC datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8590893363765985280) (5 pp, sha256 `ddf45245f556fbdf`, retrieved 2026-10-17, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-sonnet-5-5` (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/si4401bdy-datasheet.pdf)