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MMBZ5257BLT1G

Public Made by Adom

by adom

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

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MMBZ5257BLT1G

onsemi · Zener Diodes · SOT-23

MMBZ5257BLT1G 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 33 V Zener diode (MMBZ5257B, VZ 31.35 V min to 34.65 V max at IZT = 3.8 mA).
2 NC unconnected No connection (SOT-23 CASE 318 Style 8).
3 Cathode passive Cathode of the Zener diode, marked by the polarity band, which is the reverse Zener voltage terminal.

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
Zener Voltage VZ 31.35 33 34.65 V @ IZT = 3.8 mA, TA = 25°C 3
Zener Test Current IZT 3.8 mA test current for VZ and ZZT 3
Zener Impedance ZZT 58 Ω @ IZT = 3.8 mA 3
Zener Impedance ZZK 700 Ω @ IZK = 0.25 mA 3
Reverse Leakage Current IR 0.1 µA @ VR = 25 V 3
Forward Voltage VF 0.9 V IF = 10 mA, all types 3
Total Power Dissipation on FR-5 Board PD 225 mW TA = 25°C, FR-5 board (Note 1) 1
Power Derating above 25°C (FR-5) PD 1.8 mW/°C FR-5 board, above 25°C 1
Total Power Dissipation on Alumina Substrate PD 300 mW TA = 25°C, alumina substrate (Note 2) 1
Power Derating above 25°C (Alumina) PD 2.4 mW/°C Alumina substrate, above 25°C 1
Junction and Storage Temperature Range TJ, Tstg -65 150 °C 1
Thermal Resistance, Junction-to-Ambient (FR-5) RθJA 556 °C/W FR-5 board (Note 1) 1
Thermal Resistance, Junction-to-Ambient (Alumina) RθJA 417 °C/W Alumina substrate (Note 2) 1
Maximum Case Temperature for Soldering 260 °C 10 seconds 1

CAD (KiCad official)

  • Symbol: MMBZ5257BLT1G
  • Footprint: Package_TO_SOT_SMD:SOT-23
  • 3D model: SOT-23 (KiCad packages3D, STEP)
  • 3D model files: mmbz5257blt1g-etched.step / mmbz5257blt1g-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); mmbz5257blt1g.step / mmbz5257blt1g.glb are the bare package body.

Provenance

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

  • Datasheet: onsemi datasheet (7 pp, sha256 1e037aa419653ef8, retrieved 2026-10-23, tier: manufacturer)
  • Extractor: parts-factory 2.0.0 / extract_pins 0.3, primary claude-sonnet-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