# BLM21RK121SN1D

**Murata Electronics** · Ferrite Beads · 0805

BLM21RK121SN1D from Murata Electronics, in a 0805. 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 electrode of the two-terminal ferrite bead (series element, 120 ohm ±25% at 100MHz), rated 200 mA with 0.15 ohm max initial DC resistance. |
| 2 | 2 | passive | Other electrode of the two-terminal ferrite bead, interchangeable with the first; operating temperature -55°C to +125°C. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Murata Electronics |
| Package | 0805 |
| Category | Filters |
| Pins | 2 |

## Electrical characteristics

Limits from the LCSC catalog entry for this part (page.json `metadata.characteristics` carries them as data).

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Impedance | Z |  | 120 |  | Ω | at 100 MHz, catalog attribute (LCSC C524532) | catalog |
| Tolerance |  | -25 |  | 25 | % | catalog attribute (LCSC C524532) | catalog |
| Rated current |  |  |  | 200 | mA | catalog attribute (LCSC C524532) | catalog |

## CAD (KiCad official)

- Symbol: `BLM21RK121SN1D`
- Footprint: `Inductor_SMD:L_0805_2012Metric`
- 3D model: 0805 (KiCad packages3D, STEP)
- 3D model files: `blm21rk121sn1d-etched.step` / `blm21rk121sn1d-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `blm21rk121sn1d.step` / `blm21rk121sn1d.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Murata Electronics datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8588948186030989312) (11 pp, sha256 `2308ec7e5c5e4bb5`, retrieved 2026-11-07, 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/blm21rk121sn1d-datasheet.pdf)