# SMD1812-050C-12V

**BNstar** · Resettable Fuses · 1812

SMD1812-050C-12V from BNstar, in a 1812. 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 | First terminal of the non-polarized resettable PTC fuse, rated 0.50 A hold / 1.00 A trip at 25℃, Vmax 12 V and Imax 40 A. |
| 2 | 2 | passive | Second terminal of the non-polarized resettable PTC fuse, rated 0.50 A hold / 1.00 A trip at 25℃, Vmax 12 V and Imax 40 A. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | BNstar |
| Package | 1812 |
| 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 |
|---|---|---|---|---|---|---|---|
| Hold current | IH |  |  | 0.5 | A | 25℃ still air; max current at which device will not trip | 1 |
| Trip current | IT | 1 |  |  | A | 25℃ still air; min current at which device always trips | 1 |
| Maximum voltage | Vmax |  |  | 12 | V | at rated current | 1 |
| Maximum fault current | Imax |  |  | 40 | A | at rated voltage | 1 |
| Minimum resistance | Rmin | 0.15 |  |  | Ω | initial (un-soldered) state | 1 |
| Maximum resistance | R1max |  |  | 1.4 | Ω | 25℃, measured one hour after reflow soldering 260℃ for 20 sec | 1 |
| Maximum time to trip | Ttrip |  |  | 0.15 | s | at 8.00 A assigned current | 1 |
| Typical power dissipation | Pdtyp |  | 0.8 |  | W | air environment | 1 |
| Hold current derating | IH |  |  | 0.69 | A | ambient temperature -40℃ | 2 |
| Hold current derating | IH |  |  | 0.59 | A | ambient temperature -20℃ | 2 |
| Hold current derating | IH |  |  | 0.55 | A | ambient temperature 0℃ | 2 |
| Hold current derating | IH |  |  | 0.5 | A | ambient temperature 25℃ | 2 |
| Hold current derating | IH |  |  | 0.45 | A | ambient temperature 40℃ | 2 |
| Hold current derating | IH |  |  | 0.43 | A | ambient temperature 50℃ | 2 |
| Hold current derating | IH |  |  | 0.35 | A | ambient temperature 60℃ | 2 |
| Hold current derating | IH |  |  | 0.3 | A | ambient temperature 70℃ | 2 |
| Hold current derating | IH |  |  | 0.23 | A | ambient temperature 85℃ | 2 |
| Recommended storage temperature |  |  |  | 40 | ℃ | recommended storage conditions | 2 |
| Recommended storage humidity |  |  |  | 70 | % R.H. | recommended storage conditions | 2 |

## CAD (KiCad official)

- Symbol: `SMD1812-050C-12V`
- Footprint: `Fuse:Fuse_1812_4532Metric`
- 3D model: 1812, generated from the KiCad footprint (body from the F.Fab outline, terminals on the pads, 0.9 mm nominal _1806_ height). Neither the vendor nor KiCad ships a 3D model for this package, so the dimensions are nominal, not the manufacturer's CAD (STEP)
- 3D model files: `smd1812-050c-12v-etched.step` / `smd1812-050c-12v-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `smd1812-050c-12v.step` / `smd1812-050c-12v.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [BNstar datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8603382455106101248) (3 pp, sha256 `6c1e67f4701fe030`, retrieved 2026-10-14, 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/smd1812-050c-12v-datasheet.pdf)