# MMBZ5228B

**Changjing** · Zener Diodes · SOT-23

MMBZ5228B from Changjing, in a SOT-23. 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 | A | passive | Zener diode anode, shown on the page 1 symbol as pin 1 on the arrow side of the diode; forward voltage is 0.9 V at IF = 10 mA. |
| 2 | NC | unconnected | Pin 2 is drawn as an isolated terminal with no connection to the diode in the page 1 symbol. |
| 3 | K | passive | Zener diode cathode, shown on the page 1 symbol as pin 3 on the bar side of the diode; the MMBZ5228B nominal Zener voltage is 3.9 V (3.71 to 4.10 V) at IZT = 20 mA, with 300 mW maximum power dissipation. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Changjing |
| Package | SOT-23 |
| Category | Diodes |
| Pins | 3 |

## 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 (nominal 3.9 V, min) | VZ | 3.71 | 3.9 | 4.1 | V | IZT = 20 mA; short pulse (Note 1) | 2 |
| Maximum Zener impedance | ZZT |  |  | 23 | Ω | IZT = 20 mA; f = 1 kHz (Note 2) | 2 |
| Maximum Zener impedance (knee) | ZZK |  |  | 1900 | Ω | IZK = 0.25 mA | 2 |
| Maximum reverse leakage current | IR |  |  | 10 | µA | VR = 1.0 V | 2 |
| Forward voltage | VF |  |  | 0.9 | V | IF = 10 mA | 1 |
| Power dissipation | PD |  |  | 300 | mW | Ta = 25℃ | 1 |
| Junction temperature | Tj |  |  | 150 | ℃ |  | 1 |
| Storage temperature range |  | -55 |  | 150 | ℃ |  | 1 |
| Thermal resistance, junction to ambient | R JA |  |  | 417 | ℃/W |  | 1 |

## CAD (KiCad official)

- Symbol: `MMBZ5228B`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `mmbz5228b-etched.step` / `mmbz5228b-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `mmbz5228b.step` / `mmbz5228b.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/8590228072092753920) (5 pp, sha256 `aaf766a75da5fd05`, 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/mmbz5228b-datasheet.pdf)