# MMBZ5238B

**Changjing** · Zener Diodes · SOT-23

MMBZ5238B 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 anode, shown on the page 1 symbol as the diode arrow side; the MMBZ5238B has a nominal Vz of 8.7 V (8.27 to 9.14 V) at Izt = 20 mA. |
| 2 | NC | unconnected | No internal connection; pin 2 is drawn as an open, unconnected terminal in the page 1 symbol. |
| 3 | K | passive | Zener cathode, on the bar side of the symbol; it goes positive relative to the anode in breakdown, and the device is rated for 300 mW power dissipation. |

## Key specifications

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

## CAD (KiCad official)

- Symbol: `MMBZ5238B`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `mmbz5238b-etched.step` / `mmbz5238b-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `mmbz5238b.step` / `mmbz5238b.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/8590397068058521600) (5 pp, sha256 `04d5d18bbbcf95e8`, 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/mmbz5238b-datasheet.pdf)