# MMBZ5227BW

**Changjing** · Bipolar (BJT) · SOT-323

MMBZ5227BW from Changjing, in a SOT-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 | A | passive | Zener diode anode, drawn connected to the diode symbol on the page 1 internal diagram; the MMBZ5227BW has a nominal Vz of 3.6V (3.42V min to 3.78V max) at IZT=20mA. |
| 2 | NC | unconnected | Not connected internally; the page 1 diagram shows no connection from pin 2 to the diode. |
| 3 | K | passive | Zener diode cathode, wired to the bar side of the diode symbol on the page 1 diagram; it is positive relative to the anode in reverse (zener) operation, with 200mW maximum power dissipation. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Changjing |
| Package | SOT-323 |
| Category | Transistors/Thyristors |
| 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, min, max) | VZ | 3.42 | 3.6 | 3.78 | V | IZT = 20 mA, short pulse; marking KG2 | 2 |
| Maximum zener impedance | ZZT |  |  | 24 | Ω | IZT = 20 mA | 2 |
| Maximum zener impedance (knee) | ZZK |  |  | 1700 | Ω | IZK = 0.25 mA | 2 |
| Maximum reverse leakage current | IR |  |  | 15 | µA | VR = 1.0 V | 2 |
| Forward voltage | VF |  |  | 0.9 | V | IF = 10mA | 1 |
| Power dissipation | PD |  |  | 200 | mW |  | 1 |
| Thermal resistance, junction to ambient air | RθJA |  |  | 625 | ℃/W |  | 1 |
| Operation junction and storage temperature range | TJ,Tstg | -55 |  | 150 | ℃ |  | 1 |

## CAD (KiCad official)

- Symbol: `MMBZ5227BW`
- Footprint: `Package_TO_SOT_SMD:SOT-323_SC-70`
- 3D model: SOT-323 (KiCad packages3D, STEP)
- 3D model files: `mmbz5227bw-etched.step` / `mmbz5227bw-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `mmbz5227bw.step` / `mmbz5227bw.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/8590234217218011136) (5 pp, sha256 `1a32e74c733857f5`, 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/mmbz5227bw-datasheet.pdf)