# SWT18N50D

**Samwin** · MOSFETs · TO-247

SWT18N50D from Samwin, in a TO-247. 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 | Gate | input | Gate to source voltage is rated ±30 V (VGS). |
| 2 | Drain | passive | Drain to source voltage is rated 500 V and continuous drain current is 18 A at TC=25oC, limited by junction temperature. |
| 3 | Source | passive | Source is the terminal of the integral reverse p-n junction diode, with continuous source current rated 18 A. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Samwin |
| Package | TO-247 |
| Category | Triode/MOS Tube/Transistor |
| 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 to source voltage | VDSS |  |  | 500 | V |  | 1 |
| Continuous drain current (TC=25C) | ID |  |  | 18 | A | TC=25C; drain current limited by junction temperature | 1 |
| Continuous drain current (TC=100C) | ID |  |  | 11 | A | TC=100C; drain current limited by junction temperature | 1 |
| Drain current pulsed | IDM |  |  | 72 | A | note 1 | 1 |
| Gate to source voltage | VGS | -30 |  | 30 | V |  | 1 |
| Single pulsed avalanche energy | EAS |  |  | 991 | mJ | note 2 | 1 |
| Repetitive avalanche energy | EAR |  |  | 52 | mJ | note 1 | 1 |
| Peak diode recovery dv/dt | dv/dt |  |  | 5 | V/ns | note 3 | 1 |
| Total power dissipation (TO-247) | PD |  |  | 312.5 | W | TC=25C | 1 |
| Derating factor above 25C (TO-247) | PD |  |  | 2.5 | W/oC | above 25oC | 1 |
| Operating junction and storage temperature | TSTG, TJ | -55 |  | 150 | oC |  | 1 |
| Maximum lead temperature for soldering | TL |  |  | 300 | oC | 1/8 from case for 5 seconds | 1 |
| Thermal resistance, junction to case (TO-247) | Rthjc |  |  | 0.4 | oC/W |  | 1 |
| Thermal resistance, junction to ambient (TO-247) | Rthja |  |  | 38 | oC/W |  | 1 |
| Drain to source breakdown voltage | BVDSS | 500 |  |  | V | VGS=0V, ID=250uA | 2 |
| Breakdown voltage temperature coefficient | ΔBVDSS/ΔTJ |  |  | 0.54 | V/oC | ID=250uA, referenced to 25oC | 2 |
| Drain to source leakage current | IDSS |  |  | 1 | uA | VDS=500V, VGS=0V | 2 |
| Drain to source leakage current at 125C | IDSS |  |  | 50 | uA | VDS=400V, TC=125oC | 2 |
| Gate to source leakage current, forward | IGSS |  |  | 100 | nA | VGS=30V, VDS=0V | 2 |
| Gate to source leakage current, reverse | IGSS | -100 |  |  | nA | VGS=-30V, VDS=0V | 2 |
| Gate threshold voltage | VGS(TH) | 2.5 |  | 4.5 | V | VDS=VGS, ID=250uA | 2 |
| Drain to source on state resistance | RDS(ON) |  | 0.24 | 0.3 | Ω | VGS=10V, ID=9A | 2 |
| Gate resistance | Rg |  | 1.1 |  | Ω | VDS=0V, Scan F mode | 2 |

## CAD (KiCad official)

- Symbol: `SWT18N50D`
- Footprint: `Package_TO_SOT_THT:TO-247-3_Vertical`
- 3D model: TO-247 (KiCad packages3D, STEP)
- 3D model files: `swt18n50d-etched.step` / `swt18n50d-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `swt18n50d.step` / `swt18n50d.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Samwin datasheet](docs/swt18n50d-datasheet.pdf) (6 pp, sha256 `d0dd1ef9cfb850d8`, retrieved 2026-10-27, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-5-5` (text), consensus `claude-sonnet-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/swt18n50d-datasheet.pdf)