# MMSZ5231B-TP

**MCC Micro Commercial Components** · Zener Diodes · SOD-123

MMSZ5231B-TP from MCC Micro Commercial Components, 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 end marked with the cathode band; 5.1V nominal Zener voltage at IZT=20mA (MMSZ5231B, ±5%), 500mW maximum power dissipation. |
| 2 | A | passive | Anode, the end opposite the cathode mark; maximum forward voltage 0.9V at IF=10mA. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | MCC Micro Commercial Components |
| Package | SOD-123 |
| 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 tolerance (B suffix) | VZ | -5 |  | 5 | % | B suffix (MMSZ5231B); standard tolerance per note 3 | 2 |
| Maximum zener impedance | ZZT |  |  | 17 | Ω | @ IZT = 20 mA | 2 |
| Maximum zener impedance (knee) | ZZK |  |  | 1600 | Ω | @ IZK = 0.25 mA | 2 |
| Maximum reverse leakage current | IR |  |  | 5 | µA | @ VR = 2.0 V | 2 |
| Maximum zener voltage temperature coefficient |  | -0.03 |  | 0.03 | %/°C |  | 2 |
| Maximum forward voltage | VF |  |  | 0.9 | V | IF = 10 mA | 1 |
| Power dissipation | PD |  |  | 500 | mW | Note 2: mounted on 5.0 mm² land areas | 1 |
| Operating junction temperature range |  | -55 |  | 150 | °C |  | 1 |
| Storage temperature range |  | -55 |  | 150 | °C |  | 1 |
| Thermal resistance, junction to ambient |  |  | 340 |  | °C/W | Note 1: FR-4 board with minimum recommended solder pad layout | 1 |
| Nominal zener voltage | VZ |  | 5.1 |  | V | @ IZT = 20 mA; measured at 90 s with lead temperature TL = 25°C | 2 |

## CAD (KiCad official)

- Symbol: `MMSZ5231B-TP`
- Footprint: `Diode_SMD:D_SOD-123F`
- 3D model: SOD-123 (KiCad packages3D, STEP)
- 3D model files: `mmsz5231b-tp-etched.step` / `mmsz5231b-tp-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `mmsz5231b-tp.step` / `mmsz5231b-tp.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [MCC Micro Commercial Components datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8588917738664706048) (5 pp, sha256 `f9745d802679035f`, retrieved 2026-10-18, 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/mmsz5231b-tp-datasheet.pdf)