# MF-USMF020-2

**BOURNS** · Resettable Fuses · 1210

MF-USMF020-2 from BOURNS, in a 1210. 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 | Non-polarized terminal of the MF-USMF020 PTC resettable fuse (Ihold 0.20 A, Vmax 30 V, Imax 10 A), interchangeable with the other terminal. |
| 2 | 2 | passive | Non-polarized terminal of the MF-USMF020 PTC resettable fuse (Ihold 0.20 A, Vmax 30 V, Imax 10 A), interchangeable with the other terminal. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | BOURNS |
| Package | 1210 |
| 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 |
|---|---|---|---|---|---|---|---|
| Resistance, minimum (at 23 °C) | RMin. | 0.4 |  |  | Ohms |  | 1 |
| Resistance, maximum (at 23 °C) | R1Max. |  |  | 5 | Ohms |  | 1 |
| Maximum voltage (Vmax) | V max. |  |  | 30 | Volts |  | 1 |
| Maximum current (Imax) | I max. |  |  | 10 | Amps |  | 1 |
| Hold current (at 23 °C) | Ihold |  | 0.2 |  | Amperes | at 23 °C | 1 |
| Trip current (at 23 °C) | Itrip |  | 0.4 |  | Amperes | at 23 °C | 1 |
| Max. time to trip (at 23 °C) |  |  |  | 8 | Seconds | At specified current, Vmax, 23 °C | 1 |
| Tripped power dissipation (at 23 °C) |  |  | 0.6 |  | Watts | at 23 °C | 1 |
| Resistance change, passive aging |  | -5 |  | 5 | % | +85 °C, 1000 hours; typical resistance change | 1 |
| Resistance change, humidity aging |  | -5 |  | 5 | % | +85 °C, 85 % R.H. 1000 hours; typical resistance change | 1 |
| Resistance change, thermal shock |  | -10 |  | 10 | % | +85 °C to -40 °C, 20 times; typical resistance change | 1 |
| Operating temperature range |  | -40 |  | 85 | °C |  | 1 |

## 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 |  | gold | Terminal material: Electroless Ni under immersion Au | 2 |

## CAD (KiCad official)

- Symbol: `MF-USMF020-2`
- Footprint: `Fuse:Fuse_1210_3225Metric`
- 3D model: 1210 (KiCad packages3D, STEP)
- 3D model files: `mf-usmf020-2-etched.step` / `mf-usmf020-2-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `mf-usmf020-2.step` / `mf-usmf020-2.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [BOURNS datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8588910041957482497) (4 pp, sha256 `74014e5b17460aca`, 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/mf-usmf020-2-datasheet.pdf)