component
SZ1SMB28CAT3G
Public Made by Adomby adom
Littelfuse TVS, SMB. 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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Contents
README
markdownSZ1SMB28CAT3G
Littelfuse · TVS · SMB
SZ1SMB28CAT3G from Littelfuse, in a SMB. 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 | TVS terminal 1 (marked cathode on the SMB outline); bidirectional part, so this terminal is symmetrical with pin 2: VRWM 28 V, VBR 31.1-34.4 V @ 1 mA, VC 45.4 V @ IPP 13.2 A, 600 W peak pulse power (10/1000 µs). |
| 2 | Anode | passive | TVS terminal 2 (marked anode on the SMB outline); bidirectional part, so this terminal is symmetrical with pin 1: IR max 5.0 µA @ VRWM 28 V. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | Littelfuse |
| Package | SMB |
| Category | Circuit Protection |
| 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 |
|---|---|---|---|---|---|---|---|
| Working Peak Reverse Voltage | VRWM | 28 | V | 4 | |||
| Maximum Reverse Leakage Current | IR | 5 | µA | @ VRWM | 4 | ||
| Breakdown Voltage | VBR | 31.1 | 32.74 | 34.4 | V | @ IT = 1.0 mA, TA = 25°C | 4 |
| Clamping Voltage | VC | 45.4 | V | @ IPP = 13.2 A | 4 | ||
| Maximum Reverse Peak Pulse Current | IPP | 13.2 | A | 4 | |||
| Peak Power Dissipation | PPK | 600 | W | TL = 25°C, pulse width = 1 ms, 10/1000 µs non-repetitive | 1 | ||
| DC Power Dissipation | PD | 3 | W | TL = 75°C, measured zero lead length, 1" square copper pad FR-4 | 1 | ||
| DC Power Dissipation | PD | 0.55 | W | TA = 25°C, FR-4 board, Littelfuse minimum recommended footprint | 1 | ||
| Thermal Resistance Junction-to-Lead | RƟJL | 25 | °C/W | 1 | |||
| Thermal Resistance Junction-to-Ambient | RƟJA | 226 | °C/W | 1 | |||
| Forward Surge Current | IFSM | 100 | A | TA = 25°C, 1/2 sine wave, PW = 8.3 ms, unidirectional only | 1 | ||
| Operating and Storage Temperature Range | TJ, Tstg | -65 | 150 | °C | 1 | ||
| Derate Above 75°C | 40 | mW/°C | Derate above 75°C | 1 | |||
| Derate Above 25°C | 4.4 | mW/°C | Derate above 25°C | 1 |
Materials and finish
As the datasheet states them (page.json metadata.appearance; the 3D model's colours follow it).
| Part | Material | Colour / plating | Datasheet says | Page |
|---|---|---|---|---|
| contacts | tin | and the terminal finish material is tin(Sn) (IPC/ | 1 |
CAD (KiCad official)
- Symbol:
SZ1SMB28CAT3G - Footprint:
Diode_SMD:D_SMB - 3D model: SMB (KiCad packages3D, STEP)
- 3D model files:
sz1smb28cat3g-etched.step/sz1smb28cat3g-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);sz1smb28cat3g.step/sz1smb28cat3g.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: Littelfuse datasheet (7 pp, sha256
b867ff8d1ae59140, retrieved 2026-10-22, tier: lcsc) - Extractor: parts-factory
2.0.0/extract_pins 0.3, primaryclaude-sonnet-5-5(text), consensusclaude-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).