# WSTM2512QLR300FYR

**Littelfuse** · Current Sense Resistors / Shunt Resistors · 2512

WSTM2512QLR300FYR from Littelfuse, in a 2512. 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 resistor; either orientation. |
| 2 | 2 | passive | Terminal 2 of an unpolarised resistor; either orientation. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Littelfuse |
| Package | 2512 |
| Category | Resistors |
| 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 value (nominal) | Ro |  | 300 |  | mΩ |  | 4 |
| Resistance tolerance | Rt | -1 |  | 1 | % | Tolerance code F = ±1% | 2 |
| TCR | TCR | -50 |  | 50 | ppm / ºC | Q = ±50 ppm/°C (TCR code Q) | 2 |
| Power rating |  |  | 2 |  | W |  | 2 |
| Resistance change, short time overload | ΔR/R | -1 |  | 1 | % | IEC60115-1 4.13; applied voltage 2.5X rated power, 5 s, 25 ± 2 °C; limit printed ±(1.0%+0.5mΩ) | 6 |
| Resistance change, moisture load life | ΔR/R | -2 |  | 2 | % | IEC60115-1 4.25; 60 ± 2 °C, RH 95%, rated voltage, 1,000 h with 90 min ON / 30 min OFF; limit printed ±(2.0%+0.5mΩ) | 6 |
| Resistance change, temperature cycle (thermal shock) | ΔR/R | -1 |  | 1 | % | IEC60115-1 4.19; 100 cycles, -55 ± 3 °C (30 min) / +155 ± 3 °C (30 min); limit printed ±(1.0%+0.5mΩ) | 6 |
| Resistance change, resistance to solder heat | ΔR/R | -1 |  | 1 | % | IEC60115-1 4.18; through reflow, 3 reflow cycles; limit printed ±(1.0%+0.5mΩ) | 6 |
| Resistance change, high temperature exposure | ΔR/R | -1 |  | 1 | % | IEC60115-1 4.25; maximum rated operational temperature, 1,000 h, no electrical load; limit printed ±(1.0%+0.5mΩ) | 6 |
| Resistance change, low temperature storage | ΔR/R | -1 |  | 1 | % | IEC60115-1 4.25; -55 ± 2 °C, 1,000 h; limit printed ±(1.0%+0.5mΩ) | 6 |
| Resistance change, load life at 70 °C | ΔR/R | -2 |  | 2 | % | IEC60115-1 4.25; Vtest = Vmax, 70 ± 2 °C, 1,000 h with 90 min ON / 30 min OFF; limit printed ±(2.0%+0.5mΩ) | 6 |
| Resistance change, substrate bending | ΔR/R | -1 |  | 1 | % | IEC60115-1 4.33; span 90 mm, bend width 2 mm, glass-epoxy board 1.60 mm; limit printed ±(1.0%+0.5mΩ) | 6 |
| Resistance change, mechanical shock | ΔR/R | -1 |  | 1 | % | IEC60115-1 4.21; force 100G, duration 6 ms; limit printed ±(1.0%+0.5mΩ) | 6 |
| Solder coverage (solderability) |  | 95 |  |  | % | IEC60115-1 4.17; dipped in molten solder 3 ± 1 s at 245 ± 5 °C; new solder coverage | 6 |
| Storage temperature (product storage environment) |  | 5 |  | 35 | °C | Storage environment, products stored under these conditions | 5 |
| Storage relative humidity (product storage environment) |  | 45 |  | 85 | % relative humidity | Storage environment, products stored under these conditions | 5 |

## CAD (KiCad official)

- Symbol: `WSTM2512QLR300FYR`
- Footprint: `Resistor_SMD:R_2512_6332Metric`
- 3D model: 2512 (KiCad packages3D, STEP)
- 3D model files: `wstm2512qlr300fyr-etched.step` / `wstm2512qlr300fyr-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `wstm2512qlr300fyr.step` / `wstm2512qlr300fyr.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/8604374171321720832) (9 pp, sha256 `f6cd93f44f6bb289`, retrieved 2026-10-20, 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/wstm2512qlr300fyr-datasheet.pdf)