# MM3Z51VB

**onsemi** · Zener Diodes · SOD-323FL

MM3Z51VB from onsemi, in a SOD-323FL. 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, marked by the band on the package; Zener voltage VZ is 49.98 V min, 51 V typ, 52.02 V max at IZT = 2 mA (MM3Z51VB). |
| 2 | A | passive | Anode; forward voltage VF is 1.0 V max at IF = 10 mA. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | onsemi |
| Package | SOD-323FL |
| 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 | 49.98 | 51 | 52.02 | V | IZT = 2 mA, TA = 25°C, pulse 10 ms | 2 |
| Zener Voltage Tolerance | VZ | -2 |  | 2 | % | B Series, nominal Zener voltage | 2 |
| Zener Impedance | ZZT |  |  | 169 | Ω | IZT = 2 mA | 2 |
| Zener Impedance (knee) | ZZK |  |  | 376 | Ω | IZK = 0.5 mA | 2 |
| Reverse Current | IR |  |  | 0.045 | µA | VR = 35.7 V | 2 |
| Forward Voltage | VF |  |  | 1 | V | IF = 10 mA | 1 |
| Power Dissipation | PD |  |  | 200 | mW | TA = 25°C | 1 |
| Storage Temperature Range | TSTG | -65 |  | 150 | °C |  | 1 |
| Maximum Junction Temperature | TJ |  |  | 150 | °C |  | 1 |
| Thermal Resistance, Junction to Ambient | RθJA |  |  | 595 | °C/W |  | 1 |

## CAD (KiCad official)

- Symbol: `MM3Z51VB`
- Footprint: `Diode_SMD:D_SOD-323F`
- 3D model: SOD-323FL (KiCad packages3D, STEP)
- 3D model files: `mm3z51vb-etched.step` / `mm3z51vb-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `mm3z51vb.step` / `mm3z51vb.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [onsemi datasheet](https://www.onsemi.com/pdf/datasheet/mm3z51vb-d.pdf) (7 pp, sha256 `35648400ecaafb92`, retrieved 2026-10-23, tier: manufacturer)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-sonnet-5-5` (text), consensus `claude-sonnet-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/mm3z51vb-datasheet.pdf)