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Contents

README

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MMSZ5258BT3G

onsemi · Zener Diodes · SOD-123

MMSZ5258BT3G from onsemi, in a SOD-123. 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 Cathode passive Cathode of the Zener diode, marked by the polarity band; the Zener voltage for the MMSZ5258B is 36 V nominal (34.20 V to 37.80 V) at IZT = 3.4 mA.
2 Anode passive Anode of the Zener diode; the device is rated at 500 mW on an FR-4 or FR-5 board.

Key specifications

Parameter Value
Manufacturer onsemi
Package SOD-123
Category Diodes
Pins 2

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 34.2 36 37.8 V @ IZT = 3.4 mA, TA = 25°C 4
Zener Test Current IZT 3.4 mA Zener voltage test current 4
Maximum Zener Impedance ZZT 70 Ω @ IZT = 3.4 mA 4
Maximum Zener Impedance (knee) ZZK 700 Ω @ IZK = 0.25 mA 4
Reverse Leakage Current IR 0.1 µA @ VR = 27 V 4
Forward Voltage VF 0.9 V IF = 10 mA 4
Zener Voltage Tolerance -5 5 % B suffix, on nominal Zener voltage 4
Total Power Dissipation on FR-5 Board PD 500 mW TL = 75°C 2
Power Derating above 75°C PD 6.7 mW/°C Derated above 75°C 2
Junction and Storage Temperature Range TJ, Tstg -55 150 °C 2
Thermal Resistance, Junction-to-Ambient RθJA 340 °C/W Note 2 2
Thermal Resistance, Junction-to-Lead RθJL 150 °C/W Note 2 2
Maximum Case Temperature for Soldering 260 °C 10 seconds 2

CAD (KiCad official)

  • Symbol: MMSZ5258BT3G
  • Footprint: Diode_SMD:D_SOD-123F
  • 3D model: SOD-123 (KiCad packages3D, STEP)
  • 3D model files: mmsz5258bt3g-etched.step / mmsz5258bt3g-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); mmsz5258bt3g.step / mmsz5258bt3g.glb are the bare package body.

Provenance

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

  • Datasheet: onsemi datasheet (9 pp, sha256 d0ec390f70af561f, retrieved 2026-10-22, 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