# MMSZ5258B

**Yangzhou Yangjie Elec Tech** · Zener Diodes · SOD-123

MMSZ5258B from Yangzhou Yangjie Elec Tech, in a SOD-123. 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 terminal at the marked (banded) end of the package and the bar side of the diode symbol; it goes positive of the anode in zener regulation (VZ 34.2 V min, 36 V typ, 37.8 V max at IZT = 3.4 mA for MMSZ5258B). |
| 2 | A | passive | Anode, the terminal opposite the marked band and the triangle side of the diode symbol; forward voltage is 0.9 V at IF = 10 mA, and power dissipation is 500 mW. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Yangzhou Yangjie Elec Tech |
| Package | SOD-123 |
| Category | Diodes |
| Pins | 2 |

## CAD (KiCad official)

- Symbol: `MMSZ5258B`
- Footprint: `Diode_SMD:D_SOD-123F`
- 3D model: SOD-123 (KiCad packages3D, STEP)
- 3D model files: `mmsz5258b-etched.step` / `mmsz5258b-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `mmsz5258b.step` / `mmsz5258b.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Yangzhou Yangjie Elec Tech datasheet](docs/mmsz5258b-datasheet.pdf) (5 pp, sha256 `f7748de397005fd5`, retrieved 2026-10-09, 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/mmsz5258b-datasheet.pdf)