# CJSMF51A

**Changjing** · ESD And Surge Protection (TVS/ESD) · SOD-123FL

CJSMF51A from Changjing, in a SOD-123FL. 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 | K | passive | Cathode: the banded end per the datasheet; pad 1 of the KiCad diode footprint. |
| 2 | A | passive | Anode. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Changjing |
| Package | SOD-123FL |
| 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 |
|---|---|---|---|---|---|---|---|
| Breakdown voltage | VBR | 56.93 |  | 62.66 | V | IT=1 mA | 2 |
| Max reverse leakage current | IR |  |  | 5 | uA | @VRWM | 2 |
| Max peak pulse current | IPP |  |  | 2.5 | A | UNI, 10/1000us waveform | 2 |
| Max clamping voltage | VC |  |  | 81.6 | V | @Ipp | 2 |
| Peak pulse power dissipation | PPPM |  |  | 200 | W | 10/1000us waveform | 1 |
| Power dissipation | PD |  |  | 1 | W | On infinite heat sink at TL=75℃ | 1 |
| Peak forward surge current | IFSM |  |  | 20 | A | 8.3 ms single half sine-wave uni-directional only | 1 |
| Operating junction and storage temperature range | TJ,TSTG | -55 |  | 150 | ℃ |  | 1 |
| Maximum instantaneous forward voltage | VF |  |  | 3.5 | V | at 25A for uni-directional only | 1 |
| Thermal resistance junction to lead | RθJL |  |  | 100 | ℃/W | junction to lead TL=50℃ | 1 |
| Thermal resistance junction to ambient | RθJA |  |  | 200 | ℃/W | junction to ambient TA=25℃ | 1 |

## CAD (KiCad official)

- Symbol: `CJSMF51A`
- Footprint: `Diode_SMD:D_SOD-123F`
- 3D model: SOD-123FL (KiCad packages3D, STEP)
- 3D model files: `cjsmf51a-etched.step` / `cjsmf51a-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `cjsmf51a.step` / `cjsmf51a.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Changjing datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8602918613107941376) (5 pp, sha256 `0e3445de771b166a`, retrieved 2026-10-26, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins`, primary `cathode-band 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/cjsmf51a-datasheet.pdf)