# BSMD1206L-550

**BHFUSE** · Resettable Fuses · 1206

BSMD1206L-550 from BHFUSE, 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 terminal of the non-polarized resettable PTC fuse; BSMD1206L-550 is rated Ihold 5.50 A, Itrip 11.0 A, Vmax 6.0 Vdc, Imax 50 A. |
| 2 | 2 | passive | Second terminal of the non-polarized resettable PTC fuse, interchangeable with pin 1; recommended pad is 1.00 mm x 1.80 mm per terminal. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | BHFUSE |
| 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 |
|---|---|---|---|---|---|---|---|
| Hold current (maximum current without tripping) | Ihold |  |  | 5.5 | A | 25℃ still air | 2 |
| Trip current (minimum current to trip) | Itrip | 11 |  |  | A | 25℃ still air | 2 |
| Maximum voltage | Vmax |  |  | 6 | Vdc | at rated current (Imax) | 2 |
| Maximum fault current | Imax |  |  | 50 | A | at rated voltage (Vmax) | 2 |
| Minimum resistance (initial, un-soldered) | Rmin | 0.001 |  |  | Ω | initial (un-soldered) state | 2 |
| Maximum resistance after tripping or reflow | R1max |  |  | 0.009 | Ω | 25℃, measured one hour after tripping or reflow soldering at 260℃ for 20 sec | 2 |
| Power dissipated in tripped state (typical) | Pd |  | 1.2 |  | W | tripped state, 25℃ still air | 2 |
| Time to trip (at trip current 27.5 A) |  |  | 5 |  | s | at 27.5 A | 2 |
| Ambient operating temperature |  | -40 |  | 85 | °C | ambient operating conditions | 3 |
| Maximum surface temperature in tripped state |  |  |  | 125 | °C | device in the tripped state | 3 |

## CAD (KiCad official)

- Symbol: `BSMD1206L-550`
- Footprint: `Fuse:Fuse_1206_3216Metric`
- 3D model: 1206 (KiCad packages3D, STEP)
- 3D model files: `bsmd1206l-550-etched.step` / `bsmd1206l-550-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `bsmd1206l-550.step` / `bsmd1206l-550.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [BHFUSE datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8619247460076781568) (7 pp, sha256 `786f5f45bdc33acf`, 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/bsmd1206l-550-datasheet.pdf)