# 04371.75WR

**Littelfuse** · Disposable Fuses · 1206

04371.75WR from Littelfuse, in a 1206. 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 | One end-cap terminal (Ag/Ni/Sn) of the 1206 fast-acting fuse; the element is non-polarized, rated 1.75A, 63V max, interrupting rating 50 A @ 63 V AC/DC. |
| 2 | 2 | passive | Other end-cap terminal (Ag/Ni/Sn) of the 1206 fast-acting fuse; the element is non-polarized and interchangeable with the other terminal, operating temperature -55°C to +150°C. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Littelfuse |
| Package | 1206 |
| 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 (250mA-8A) |  | 4 |  |  | hours | 100% of ampere rating, 250mA - 8A, at 25ºC | 1 |
| Opening time at 250% of ampere rating (750mA-8A) |  |  |  | 5 | seconds | 250% of ampere rating, 750mA - 8A, at 25ºC | 1 |
| Opening time at 350% of ampere rating (750mA-8A) |  |  |  | 1 | seconds | 350% of ampere rating, 750mA - 8A, at 25ºC | 1 |
| Max. Voltage Rating |  |  |  | 63 | V | 1.75A (amp code 1.75) row | 1 |
| Interrupting Rating |  |  |  | 50 | A | 63 V AC/DC; AC tested at rated voltage with unity power factor; DC tested at rated voltage with time constant < 0.8 msec | 1 |
| Operating Temperature |  | -55 |  | 150 | ºC |  | 1 |
| Continuous operation current (re-rating) |  |  |  | 80 | % of rated current | continuous operation; recommended, in addition to standard 20% re-rating for continuous operation | 1 |
| Nominal Resistance |  |  | 0.071 |  | Ohms | measured with < 10% rated current | 1 |
| Nominal Melting I2t |  |  | 0.075 |  | A2Sec. |  | 1 |
| Nominal Voltage Drop At Rated Current |  |  | 0.27 |  | V | at rated current, after temperature has stabilized | 1 |
| Nominal Power Dissipation At Rated Current |  |  | 0.473 |  | W | at rated current | 1 |
| Ampere Rating |  |  | 1.75 |  | A | amp code 1.75 (marking L) | 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: Ceramic/Lead-free | 3 |

## CAD (KiCad official)

- Symbol: `04371.75WR`
- Footprint: `Fuse:Fuse_1206_3216Metric`
- 3D model: 1206 (KiCad packages3D, STEP)
- 3D model files: `04371-75wr-etched.step` / `04371-75wr-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `04371-75wr.step` / `04371-75wr.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/8588910161431826432) (3 pp, sha256 `4118dc56d128f864`, retrieved 2026-10-18, 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/04371-75wr-datasheet.pdf)