component
MMBZ5251B
Public Made by Adomby adom
Changjing Zener Diodes, SOT-23. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
3D Model
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Symbol & Footprint
Schematic Symbol
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PCB Footprint
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Datasheet
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README
markdownMMBZ5251B
Changjing · Zener Diodes · SOT-23
MMBZ5251B 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 | Anode of the zener diode, per the page 1 symbol (pin 1 on the arrow side); the MMBZ5251B has VZ 22 V nom (20.90 to 23.10 V) at IZT 5.6 mA. |
| 2 | NC | unconnected | Pin 2 is drawn on the page 1 symbol with no connection to the diode, so it is not connected internally. |
| 3 | K | passive | Cathode of the zener diode, per the page 1 symbol (pin 3 on the bar side); power dissipation is 300 mW maximum. |
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 | VZ | 20.9 | 22 | 23.1 | V | IZT = 5.6 mA (short-duration test pulse) | 2 |
| Maximum zener impedance | ZZT | 29 | Ω | IZT = 5.6 mA | 2 | ||
| Maximum zener impedance | ZZK | 600 | Ω | IZK = 0.25 mA | 2 | ||
| Maximum reverse leakage current | IR | 0.1 | µA | VR = 17 V | 2 | ||
| Forward voltage | VF | 0.9 | V | IF = 10 mA; Ta = 25℃ | 1 | ||
| Power dissipation | PD | 300 | mW | Ta = 25℃ | 1 | ||
| Thermal resistance junction to ambient | RθJA | 417 | ℃/W | Ta = 25℃ | 1 | ||
| Junction temperature | Tj | 150 | ℃ | Ta = 25℃ | 1 | ||
| Storage temperature range | -55 | 150 | ℃ | Ta = 25℃ | 1 |
CAD (KiCad official)
- Symbol:
MMBZ5251B - Footprint:
Package_TO_SOT_SMD:SOT-23 - 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files:
mmbz5251b-etched.step/mmbz5251b-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);mmbz5251b.step/mmbz5251b.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: Changjing datasheet (5 pp, sha256
aaf766a75da5fd05, retrieved 2026-10-18, tier: lcsc) - Extractor: parts-factory
2.0.0/extract_pins 0.3, primaryclaude-sonnet-5-5(text+vision), consensusclaude-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).