# WST4040

**Winsok Semicon** · MOSFETs · SOT-23-3L

WST4040 from Winsok Semicon, in a SOT-23-3L. 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 | G | input | Gate; gate-source voltage limited to ±20 V, threshold 0.6 to 1.6 V (1.0 V typ) at 250 µA. |
| 2 | S | passive | Source; continuous source current up to 1 A through the body diode, pulsed 16 A. |
| 3 | D | passive | Drain; drain-source voltage rated 40 V, continuous drain current 5.8 A and pulsed 16 A. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Winsok Semicon |
| Package | SOT-23-3L |
| Category | Transistors/Thyristors |
| Pins | 3 |

## Electrical characteristics

Limits as printed in the datasheet (page.json `metadata.characteristics` carries them as data).

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Drain-Source Voltage | VDS |  |  | 40 | V |  | 1 |
| Gate-Source Voltage | VGS | -20 |  | 20 | V |  | 1 |
| Continuous Drain Current, TC=25℃ | ID |  |  | 5.8 | A | VGS @ 4.5V | 1 |
| Continuous Drain Current, TC=70℃ | ID |  |  | 2.5 | A | VGS @ 4.5V | 1 |
| Pulsed Drain Current | IDM |  |  | 16 | A |  | 1 |
| Total Power Dissipation, TA=25℃ | PD |  |  | 1 | W |  | 1 |
| Storage Temperature Range | TSTG | -55 |  | 150 | ℃ |  | 1 |
| Operating Junction Temperature Range | TJ | -55 |  | 150 | ℃ |  | 1 |
| Thermal Resistance Junction-ambient | RθJA |  |  | 125 | ℃/W |  | 1 |
| Thermal Resistance Junction-Case | RθJC |  |  | 75 | ℃/W |  | 1 |
| Single Pulse Avalanche Energy | EAS | 9 |  |  | mJ | VDD=25V, L=0.1mH, IAS=2A | 2 |
| Continuous Source Current | IS |  |  | 1 | A | VG=VD=0V, Force Current | 2 |
| Pulsed Source Current | ISM |  |  | 16 | A |  | 2 |
| Diode Forward Voltage | VSD |  |  | 1.2 | V | VGS=0V, IS=1A, TJ=25℃ | 2 |
| Drain-Source Breakdown Voltage | BVDSS | 40 |  |  | V | VGS=0V, ID=250uA | 2 |
| Static Drain-Source On-Resistance | RDS(ON) |  | 35 | 50 | mΩ | VGS=10V, ID=3A | 2 |
| Gate Threshold Voltage | VGS(th) | 0.6 | 1 | 1.6 | V | VGS=VDS, ID=250uA | 2 |
| Drain-Source Leakage Current, TJ=25℃ | IDSS |  |  | 1 | uA | VDS=32V, VGS=0V, TJ=25℃ | 2 |
| Drain-Source Leakage Current, TJ=55℃ | IDSS |  |  | 5 | uA | VDS=32V, VGS=0V, TJ=55℃ | 2 |
| Gate-Source Leakage Current | IGSS | -100 |  | 100 | nA | VGS=±20V, VDS=0V | 2 |
| Gate-Source Charge | Qgs |  | 0.8 | 3.5 | nC | VDS=20V, VGS=4.5V, ID=2A | 2 |
| Gate-Drain Charge | Qgd |  | 1.65 | 4.2 | nC | VDS=20V, VGS=4.5V, ID=2A | 2 |
| Turn-On Delay Time | Td(on) |  | 1.5 | 4.8 | ns | VDD=20V, VGS=10V, RG=3.3Ω, ID=1A | 2 |
| Turn-Off Delay Time | Td(off) |  | 18 | 44 | ns | VDD=20V, VGS=10V, RG=3.3Ω, ID=1A | 2 |
| Fall Time | Tf |  | 5.9 | 8 | ns | VDD=20V, VGS=10V, RG=3.3Ω, ID=1A | 2 |

## CAD (KiCad official)

- Symbol: `WST4040`
- Footprint: `Package_TO_SOT_SMD:SOT-23-3`
- 3D model: SOT-23-3L (KiCad packages3D, STEP)
- 3D model files: `wst4040-etched.step` / `wst4040-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `wst4040.step` / `wst4040.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Winsok Semicon datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8588884095736139776) (5 pp, sha256 `740fd14bc154952e`, retrieved 2026-10-09, 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/wst4040-datasheet.pdf)