# 1206L400

**Littelfuse** · Resettable Fuses · 1206

1206L400 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 | 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 | 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 |
|---|---|---|---|---|---|---|---|
| Minimum resistance (R min) | R min | 0.001 |  |  | Ω |  | 2 |
| Maximum resistance after trip (R1max) | R1max |  |  | 0.016 | Ω |  | 2 |
| Maximum voltage (V max) | V max |  |  | 6 | Vdc |  | 2 |
| Maximum fault current (I max) | I max |  |  | 50 | A |  | 2 |
| Operating temperature |  | -40 |  | 85 | °C | Environmental Specifications: Operating Temperature | 4 |
| Maximum device surface temperature in tripped state |  |  |  | 125 | °C | In tripped state | 4 |
| Passive aging resistance change (typical) |  | -10 |  | 10 | % | +85°C, 1000 hours passive aging; -/+10% typical resistance change | 4 |
| Humidity aging resistance change (typical) |  | -15 |  | 15 | % | +85°C, 85% R.H., 100 hours; -/+15% typical resistance change | 4 |
| Thermal shock resistance change (typical) |  | -30 |  |  | % | MIL-STD-202 Method 107, +85°C/-40°C 20 times; -30% typical resistance change | 4 |
| Peak classification reflow temperature (Pb-free) | TP |  |  | 260 | °C | Pb-free assembly reflow profile; printed as 260+0/-5 °C | 4 |
| Hold current | I hold |  | 4 |  | A |  | 2 |
| Trip current | I trip |  | 8 |  | A |  | 2 |
| Maximum time-to-trip current |  |  | 20 |  | A | Time-to-trip test: 2.00 s | 2 |
| Power dissipation (typical) | P d |  | 0.8 |  | W |  | 2 |

## 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 | Copper |  | Terminal Material Solder-Plated Copper | 4 |

## CAD (KiCad official)

- Symbol: `1206L400`
- Footprint: `Fuse:Fuse_1206_3216Metric`
- 3D model: 1206 (KiCad packages3D, STEP)
- 3D model files: `1206l400-etched.step` / `1206l400-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `1206l400.step` / `1206l400.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/8589031546224824320) (8 pp, sha256 `ba01087abeed0a81`, 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/1206l400-datasheet.pdf)