# 1206L050YR

**Littelfuse** · Resettable Fuses · 1206

1206L050YR 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 of two interchangeable solder-plated copper end terminals of the resettable PTC; the 1206L050 is rated 0.50 A hold, 1.00 A trip, 6 Vdc max, 100 A max fault current. |
| 2 | 2 | passive | Second interchangeable solder-plated copper end terminal of the resettable PTC (non-polarized); the 1206L050 has 0.10 ohm min and 0.150 ohm R1max resistance, with 0.70 ohm listed as the maximum resistance after trip or reflow. |

## 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 in initial (un-soldered) state | R min | 0.15 |  |  | Ω | Initial un-soldered state | 1 |
| Maximum resistance at 20°C after trip or reflow | R 1max |  |  | 0.7 | Ω | 20°C, measured one hour after tripping or reflow soldering of 260°C for 20 sec | 1 |
| Hold current | I hold |  |  | 0.5 | A | 20°C still air; maximum current device passes without tripping | 1 |
| Trip current | I trip | 1 |  |  | A | 20°C still air; minimum current at which device trips | 1 |
| Maximum voltage | V max |  |  | 6 | Vdc | Maximum voltage device withstands without damage at rated current (I max) | 1 |
| Maximum fault current | I max |  |  | 100 | A | Maximum fault current device withstands without damage at rated voltage (Vmax) | 1 |
| Maximum time to trip |  |  |  | 0.1 | s | At 8.00 A | 1 |
| Hold current vs ambient temperature | I hold |  |  | 0.71 | A | Ambient -40°C | 2 |
| Hold current vs ambient temperature | I hold |  |  | 0.64 | A | Ambient -20°C | 2 |
| Hold current vs ambient temperature | I hold |  |  | 0.57 | A | Ambient 0°C | 2 |
| Hold current vs ambient temperature | I hold |  |  | 0.5 | A | Ambient 20°C | 2 |
| Hold current vs ambient temperature | I hold |  |  | 0.42 | A | Ambient 40°C | 2 |
| Hold current vs ambient temperature | I hold |  |  | 0.39 | A | Ambient 50°C | 2 |
| Hold current vs ambient temperature | I hold |  |  | 0.35 | A | Ambient 60°C | 2 |
| Hold current vs ambient temperature | I hold |  |  | 0.31 | A | Ambient 70°C | 2 |
| Hold current vs ambient temperature | I hold |  |  | 0.25 | A | Ambient 85°C | 2 |
| Passive aging resistance change |  | -5 |  | 5 | % | Passive aging +85°C, 1000 hours; typical resistance change | 3 |
| Humidity aging resistance change |  | -5 |  | 5 | % | Humidity aging +85°C, 85% R.H., 1000 hours; typical resistance change | 3 |
| Operating/storage temperature |  | -40 |  | 85 | °C | Operating/storage | 3 |
| Maximum device surface temperature in tripped state |  |  |  | 125 | °C | Tripped state | 3 |
| Preheat temperature | Ts | 150 |  | 200 | °C | Pb-free reflow preheat | 3 |
| Preheat time | ts | 60 |  | 180 | s | Pb-free reflow, preheat from Ts(min) to Ts(max) | 3 |
| Time above liquidus | tL | 60 |  | 150 | s | Pb-free reflow, above TL 217°C | 3 |
| Time within 5°C of peak temperature | tp | 20 |  | 40 | s | Pb-free reflow | 3 |
| Average ramp-up rate (TS(max) to TP) |  |  |  | 3 | °C/second | Pb-free reflow, maximum | 3 |
| Ramp-down rate |  |  |  | 6 | °C/second | Pb-free reflow, maximum | 3 |
| Time 25°C to peak temperature |  |  |  | 8 | minutes | Pb-free reflow, maximum | 3 |
| Power dissipated in tripped state | Pd |  | 0.6 |  | W | Tripped state, 20°C still air | 1 |
| Trip-time reference temperature liquidus | TL |  | 217 |  | °C | Pb-free reflow, time maintained above TL | 3 |
| Thermal shock resistance change |  |  | -30 |  | % | MIL-STD-202 Method 107, +85°C/-40°C 20 times; typical resistance change | 3 |

## 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 (Solder Material: | 3 |

## CAD (KiCad official)

- Symbol: `1206L050YR`
- Footprint: `Fuse:Fuse_1206_3216Metric`
- 3D model: 1206 (KiCad packages3D, STEP)
- 3D model files: `1206l050yr-etched.step` / `1206l050yr-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `1206l050yr.step` / `1206l050yr.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/8588909033121701888) (6 pp, sha256 `e7684db822499dee`, 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/1206l050yr-datasheet.pdf)