# FRM121WJR025TM

**FOJAN** · Current Sense Resistors / Shunt Resistors · 1206

FRM121WJR025TM from FOJAN, 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 | Terminal 1 of an unpolarised resistor; either orientation. |
| 2 | 2 | passive | Terminal 2 of an unpolarised resistor; either orientation. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | FOJAN |
| Package | 1206 |
| 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 Range (1206, 1 W row) |  | 1 |  | 100 | mΩ |  | 5 |
| Tolerance (code J = ±5%) |  | -5 |  | 5 | % |  | 2 |
| Temperature Coefficient of Resistance (T.C.R.) |  | -50 |  | 50 | ppm/°C |  | 5 |
| Power Rating | P70 |  |  | 1 | W | at P70 (70 °C) | 5 |
| Rated Current |  |  |  | 31 | A |  | 5 |
| Max Overload Current |  |  |  | 70 | A |  | 5 |
| Operating Temperature Range |  | -55 |  | 170 | °C |  | 5 |
| Dielectric Withstanding Voltage |  |  |  | 500 | V DC |  | 2 |
| Resistance change, High Temperature Exposure (Storage) | ΔR | -1 |  | 1 | % | 170 °C, 1000 h, measured 24 h after test | 6 |
| Resistance change, Low Temperature Exposure (Storage) | ΔR | -0.5 |  | 0.5 | % | -55 °C, 1000 h, measured 24 h after test | 6 |
| Resistance change, Temperature Cycling | ΔR | -0.5 |  | 0.5 | % | 1000 cycles, -55 °C to 125 °C, measured 24 h after test | 6 |
| Resistance change, Short time overload | ΔR | -0.5 |  | 0.5 | % | 5 × rated power for 5 s | 6 |
| Resistance change, Moisture Resistance | ΔR | -1 |  | 1 | % | 24 h per cycle, 10 cycles, zero power | 6 |
| Resistance change, Biased Humidity | ΔR | -0.5 |  | 0.5 | % | 10% rated power, 85 °C, RH 85%, 1000 h | 6 |
| Resistance change, Load Life | ΔR | -1 |  | 1 | % | 1000 h at +70 °C, 1.5 h ON / 0.5 h OFF | 7 |
| Resistance change, Resistance to Soldering Heat | ΔR | -0.5 |  | 0.5 | % | 260 ±5 °C solder, 10 ±1 s dwell | 7 |
| Resistance change, Mechanical Shock | ΔR | -0.5 |  | 0.5 | % | 100 g, 6 ms half sine | 7 |
| Resistance change, Resistance to Vibration | ΔR | -0.5 |  | 0.5 | % | 5 g, 10-2000 Hz, 20 min, 12 cycles per axis | 7 |
| Resistance change, Board Flex | ΔR | -0.5 |  | 0.5 | % | Min 2 mm deflection, 60 s | 7 |
| Resistance change, Thermal Shock | ΔR | -1 |  | 1 | % | -55 °C / +155 °C, 1000 cycles | 7 |
| Resistance change, ESD Test | ΔR | -1 |  | 1 | % | Direct contact ±6 kV; air discharge +12/+16/+25 kV | 7 |
| Nominal resistance (marking R025) | R |  | 25 |  | mΩ |  | 6 |

## CAD (KiCad official)

- Symbol: `FRM121WJR025TM`
- Footprint: `Resistor_SMD:R_1206_3216Metric`
- 3D model: 1206 (KiCad packages3D, STEP)
- 3D model files: `frm121wjr025tm-etched.step` / `frm121wjr025tm-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `frm121wjr025tm.step` / `frm121wjr025tm.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [FOJAN datasheet](docs/frm121wjr025tm-datasheet.pdf) (12 pp, sha256 `13a1c74e6b23cc10`, retrieved 2026-10-17, tier: lcsc)
- **Datasheet language:** Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
- **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/frm121wjr025tm-datasheet.pdf)