# SZ1SMB15CAT3G

**Littelfuse** · TVS · SMB

SZ1SMB15CAT3G 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 | Terminal 1 (marked Cathode on the package drawing); on the bi-directional CA device it is interchangeable with pin 2, with VRWM 15 V, VBR 16.7-18.5 V at 1.0 mA and VC 24.4 V at 24.0 A. |
| 2 | Anode | passive | Terminal 2 (marked Anode on the package drawing); on the bi-directional CA device it is interchangeable with pin 1, with no cathode band, and IR is 5.0 µA max at VRWM 15 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 |  | 15 |  | V |  | 4 |
| Maximum Reverse Leakage Current | IR |  |  | 5 | µA | @ VRWM | 4 |
| Breakdown Voltage | VBR | 16.7 | 17.58 | 18.5 | V | @ IT = 1.0 mA, TA = 25°C | 4 |
| Clamping Voltage | VC |  |  | 24.4 | V | @ IPP = 24.0 A | 4 |
| Maximum Reverse Peak Pulse Current | IPP |  |  | 24 | A |  | 4 |
| Peak Power Dissipation | PPK |  |  | 600 | W | @ TL = 25°C, Pulse Width = 1 ms (10/1000 µs, non-repetitive) | 1 |
| DC Power Dissipation (lead) | PD |  |  | 3 | W | @ TL = 75°C, measured zero lead length, 1" square copper pad FR-4 | 1 |
| DC Power Dissipation (ambient) | PD |  |  | 0.55 | W | @ TA = 25°C, FR-4 board, minimum recommended footprint | 1 |
| Forward Surge Current | IFSM |  |  | 100 | A | @ TA = 25°C, 1/2 sine wave, PW = 8.3 ms, uni-directional only | 1 |
| Operating and Storage Temperature Range | TJ, Tstg | -65 |  | 150 | °C |  | 1 |
| Thermal Resistance Junction-to-Lead | RθJL |  | 25 |  | °C/W |  | 1 |
| Thermal Resistance Junction-to-Ambient | RθJA |  | 226 |  | °C/W |  | 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: `SZ1SMB15CAT3G`
- Footprint: `Diode_SMD:D_SMB`
- 3D model: SMB (KiCad packages3D, STEP)
- 3D model files: `sz1smb15cat3g-etched.step` / `sz1smb15cat3g-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `sz1smb15cat3g.step` / `sz1smb15cat3g.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Littelfuse datasheet](docs/sz1smb15cat3g-datasheet.pdf) (7 pp, sha256 `b867ff8d1ae59140`, retrieved 2026-10-26, tier: lcsc)
- **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](docs/sz1smb15cat3g-datasheet.pdf)