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MMBZ5251B

Public Made by Adom

by adom

Changjing Zener Diodes, SOT-23. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.

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MMBZ5251B

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.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); mmbz5251b.step / mmbz5251b.glb are 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, 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