# MMBZ5239BLT1G

**onsemi** · Zener Diodes · SOT-23

MMBZ5239BLT1G from onsemi, 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 | ANODE | passive | Anode of the Zener diode; per the STYLE 8 pinout it is the terminal opposite the cathode at pin 3. |
| 2 | NC | unconnected | No Connection (NC) per the STYLE 8 pinout; the datasheet assigns this pin no electrical function. |
| 3 | CATHODE | passive | Cathode of the Zener diode, indicated by the polarity band on the package; per the STYLE 8 pinout it is the terminal opposite the anode at pin 1. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | onsemi |
| 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 |
|---|---|---|---|---|---|---|---|
| Reverse Zener Voltage | VZ | 8.64 | 9.1 | 9.56 | V | @ IZT = 20 mA; pulse test, TA = 25°C | 3 |
| Maximum Zener Impedance | ZZT |  | 10 | 10 | Ω | @ IZT = 20 mA | 3 |
| Maximum Zener Impedance | ZZK |  | 600 | 600 | Ω | @ IZK = 0.25 mA | 3 |
| Reverse Leakage Current | IR |  |  | 3 | µA | @ VR = 7 V | 3 |
| Forward Voltage | VF |  |  | 0.9 | V | @ IF = 10 mA | 3 |
| Total Power Dissipation on FR-5 Board | PD |  |  | 225 | mW | TA = 25°C, FR-5 board (Note 1); derated 1.8 mW/°C above 25°C | 1 |
| Total Power Dissipation on Alumina Substrate | PD |  |  | 300 | mW | TA = 25°C, alumina substrate (Note 2); derated 2.4 mW/°C above 25°C | 1 |
| Thermal Resistance, Junction-to-Ambient (FR-5 board) | RθJA |  |  | 556 | °C/W | FR-5 board (Note 1) | 1 |
| Thermal Resistance, Junction-to-Ambient (alumina substrate) | RθJA |  |  | 417 | °C/W | Alumina substrate (Note 2) | 1 |
| Junction and Storage Temperature Range | TJ, Tstg | -65 |  | 150 | °C |  | 1 |

## CAD (KiCad official)

- Symbol: `MMBZ5239BLT1G`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `mmbz5239blt1g-etched.step` / `mmbz5239blt1g-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `mmbz5239blt1g.step` / `mmbz5239blt1g.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [onsemi datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8586186815330402304) (6 pp, sha256 `bdbb8fa2d7f751fd`, retrieved 2026-10-17, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-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/mmbz5239blt1g-datasheet.pdf)