# SI9945BDY

**TECH PUBLIC** · MOSFETs · SOP-8

SI9945BDY 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 | S1 | passive | Source of N-channel MOSFET 1; VDS rated 60 V, ID 6 A continuous. |
| 2 | G1 | input | Gate of N-channel MOSFET 1; absolute maximum VGS ±20 V, threshold 1.2 to 2.5 V. |
| 3 | S2 | passive | Source of N-channel MOSFET 2; VDS rated 60 V, ID 6 A continuous. |
| 4 | G2 | input | Gate of N-channel MOSFET 2; absolute maximum VGS ±20 V, threshold 1.2 to 2.5 V. |
| 5 | D2 | passive | Drain of N-channel MOSFET 2; VDS rated 60 V, pulsed drain current 24 A. |
| 6 | D2 | passive | Drain of N-channel MOSFET 2, tied to pin 5; VDS rated 60 V, pulsed drain current 24 A. |
| 7 | D1 | passive | Drain of N-channel MOSFET 1; VDS rated 60 V, pulsed drain current 24 A. |
| 8 | D1 | passive | Drain of N-channel MOSFET 1, tied to pin 7; VDS rated 60 V, pulsed drain current 24 A. |

## Key specifications

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

## CAD (KiCad official)

- Symbol: `SI9945BDY`
- Footprint: `Package_SO:SOIC-8_3.9x4.9mm_P1.27mm`
- 3D model: SOP-8 (KiCad packages3D, STEP)
- 3D model files: `si9945bdy-etched.step` / `si9945bdy-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `si9945bdy.step` / `si9945bdy.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/8590238155753353216) (5 pp, sha256 `958559f0405bd59f`, retrieved 2026-10-15, 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/si9945bdy-datasheet.pdf)