# 04381.25WR

**Littelfuse** · Disposable Fuses · 0603

04381.25WR from Littelfuse, in a 0603. 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 | 1 | passive | Terminal 1 of an unpolarised fuse; either orientation. |
| 2 | 2 | passive | Terminal 2 of an unpolarised fuse; either orientation. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Littelfuse |
| Package | 0603 |
| Category | Circuit Protection |
| Pins | 2 |

## Electrical characteristics

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

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Opening time at 100% of ampere rating (minimum) |  | 4 |  |  | hours | 100% of ampere rating; opening time at 25ºC | 1 |
| Opening time at 250% of ampere rating (maximum) |  |  |  | 5 | seconds | 250% of ampere rating; opening time at 25ºC | 1 |
| Max. voltage rating |  |  |  | 63 | VDC |  | 1 |
| DC interrupting rating |  |  |  | 50 | A | 63VDC; DC rating tested at rated voltage with time constant < 0.8 msec | 1 |
| Operating temperature |  | -55 |  | 150 | °C | Operating temperature range | 1 |
| Continuous operating current |  |  |  | 80 | % of rated current | Devices operated continuously; standard 20% re-rating applies additionally | 1 |
| Nominal resistance |  |  | 0.2 |  | Ohms | Measured with < 10% rated current | 1 |
| Nominal melting I2t |  |  | 0.051 |  | A2Sec. | Measured at 1 msec. opening time | 1 |
| Nominal voltage drop at rated current |  |  | 0.365 |  | V | Measured at rated current after temperature has stabilized | 1 |
| Nominal power dissipation at rated current |  |  | 0.456 |  | W | At rated current | 1 |

## Materials and finish

As the datasheet states them (page.json `metadata.appearance`; the 3D model's colours follow it).

| Part | Material | Colour / plating | Datasheet says | Page |
|---|---|---|---|---|
| contacts |  | tin | Terminations: Ag / Ni / Sn (100% Lead-free) Element Cover Coating: Lead-free Glass | 3 |

## CAD (KiCad official)

- Symbol: `04381.25WR`
- Footprint: `Fuse:Fuse_0603_1608Metric`
- 3D model: 0603 (KiCad packages3D, STEP)
- 3D model files: `04381-25wr-etched.step` / `04381-25wr-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `04381-25wr.step` / `04381-25wr.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Littelfuse datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8588910129160851456) (3 pp, sha256 `a9efab228ef1992a`, retrieved 2026-10-18, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins`, primary `two-terminal convention` (convention), consensus `off` (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/04381-25wr-datasheet.pdf)