# MMSZ5250BS

**Changjing** · Zener Diodes · SOD-323

MMSZ5250BS from Changjing, in a SOD-323. 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/marked end per the datasheet; pad 1 of the KiCad diode footprint. |
| 2 | A | passive | Anode. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Changjing |
| Package | SOD-323 |
| Category | Diodes |
| 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 |
|---|---|---|---|---|---|---|---|
| Zener Voltage | VZ | 19 | 20 | 21 | V | @ IZT = 6.2 mA | 2 |
| Maximum Zener Impedance | ZZT |  |  | 25 | Ω | @ IZT = 6.2 mA | 2 |
| Maximum Zener Impedance (knee) | ZZK |  |  | 600 | Ω | @ IZK = 0.25 mA | 2 |
| Maximum Reverse Current | IR |  |  | 0.1 | uA | @ VR = 15 V | 2 |
| Forward Voltage | VF |  |  | 0.9 | V | IF = 10mA, pulses Tp≤1.0ms | 1 |
| Power Dissipation | PD |  |  | 200 | mW | Ta=25℃, device mounted on ceramic PCB | 1 |
| Thermal Resistance, Junction to Ambient Air | RθJA |  |  | 625 | ℃/W | Device mounted on ceramic PCB | 1 |
| Operating and Storage Temperature Range | Tj,TSTG | -65 |  | 150 | ℃ |  | 1 |
| Zener Test Current | IZT |  | 6.2 |  | mA |  | 2 |
| Zener Knee Test Current | IZK |  | 0.25 |  | mA |  | 2 |
| Reverse Voltage for IR | VR |  | 15 |  | V |  | 2 |

## CAD (KiCad official)

- Symbol: `MMSZ5250BS`
- Footprint: `Diode_SMD:D_SOD-323`
- 3D model: SOD-323 (KiCad packages3D, STEP)
- 3D model files: `mmsz5250bs-etched.step` / `mmsz5250bs-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `mmsz5250bs.step` / `mmsz5250bs.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/8579710414627586048) (3 pp, sha256 `55a991103f766e72`, retrieved 2026-10-22, 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/mmsz5250bs-datasheet.pdf)