# 0438002.WR

**Littelfuse** · Disposable Fuses · 0603

0438002.WR 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 | Fuse terminal 1 (Ag/Ni/Sn termination); non-polarized, 2 A rated, 32 V max, 50 A interrupting rating at 32VDC/12VAC. |
| 2 | 2 | passive | Fuse terminal 2 (Ag/Ni/Sn termination); non-polarized and interchangeable with terminal 1, in series with the protected circuit. |

## 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 |  | 4 |  |  | hours | 100% of ampere rating; opening time at 25ºC | 1 |
| Opening time at 250% of ampere rating |  |  |  | 5 | s | 250% of ampere rating; opening time at 25ºC | 1 |
| Operating temperature |  | -55 |  | 150 | ºC |  | 1 |
| Continuous operating current |  |  |  | 80 | % | Recommended continuous operation, percent of rated current | 1 |
| Max. voltage rating |  |  |  | 32 | VDC | Amp code 002. | 1 |
| Interrupting rating |  |  |  | 50 | A | @ 32VDC/12VAC | 1 |
| Peak temperature (Pb-free reflow) | TP |  |  | 260 | °C | Printed as 260+0/-5 °C; Pb-free reflow assembly | 2 |
| Time within 5°C of peak temperature | tp | 10 |  | 30 | s | Pb-free reflow assembly | 2 |
| Time 25°C to peak temperature |  |  |  | 8 | min | Pb-free reflow assembly | 2 |
| Average ramp-up rate (TL to peak) |  |  |  | 3 | °C/second | Pb-free reflow assembly | 2 |
| Ramp-down rate |  |  |  | 6 | °C/second | Pb-free reflow assembly | 2 |
| Wave soldering time |  |  |  | 10 | s | Wave soldering at 260°C | 2 |
| Rated current (ampere rating) |  |  | 2 |  | A | Amp code 002. | 1 |
| Nominal resistance |  |  | 0.051 |  | Ohms | Measured with <10% rated current; amp code 002. | 1 |
| Nominal melting I2t | I2t |  | 0.149 |  | A2Sec. | Measured at 1 msec. opening time; amp code 002. | 1 |
| Nominal voltage drop at rated current |  |  | 0.107 |  | V | Measured at rated current after temperature has stabilized; amp code 002. | 1 |
| Nominal power dissipation at rated current |  |  | 0.214 |  | W | At rated current; amp code 002. | 1 |

## CAD (KiCad official)

- Symbol: `0438002.WR`
- Footprint: `Fuse:Fuse_0603_1608Metric`
- 3D model: 0603 (KiCad packages3D, STEP)
- 3D model files: `0438002-wr-etched.step` / `0438002-wr-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `0438002-wr.step` / `0438002-wr.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/8588917220378755072) (3 pp, sha256 `052a726ae5f412a4`, retrieved 2026-10-15, 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/0438002-wr-datasheet.pdf)