# SZ1SMB75CAT3G

**Littelfuse** · ESD And Surge Protection (TVS/ESD) · SMB

SZ1SMB75CAT3G 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 of the bi-directional TVS; the datasheet's package marking labels it Cathode, but the cathode band applies only to uni-directional components, so for the CA-suffix SZ1SMB75CAT3G this terminal is not polarized and is interchangeable with pin 2. |
| 2 | Anode | passive | Terminal 2 of the bi-directional TVS; the datasheet's package marking labels it Anode, but the cathode band applies only to uni-directional components, so for the CA-suffix SZ1SMB75CAT3G this terminal is not polarized and is interchangeable with pin 1. |

## 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 |
|---|---|---|---|---|---|---|---|
| Breakdown Voltage (bi-directional, 75 V) | VBR | 83.3 | 91.65 | 92.07 | V | @ IT = 1.0 mA (Note 7: TA = 25°C) | 4 |
| Maximum Reverse Leakage Current | IR |  |  | 5 | µA | @ VRWM | 4 |
| Clamping Voltage | VC |  |  | 121 | V | @ IPP = 4.9 A (Note 8) | 4 |
| Maximum Reverse Peak Pulse Current | IPP |  |  | 4.9 | A |  | 4 |
| Working Peak Reverse Voltage | VRWM |  | 75 |  | V |  | 4 |
| Peak Power Dissipation | PPK |  |  | 600 | W | TL = 25°C, Pulse Width = 1 ms (Note 1: 10/1000 µs, non-repetitive) | 1 |
| DC Power Dissipation (lead-measured) | PD |  |  | 3 | W | @ TL = 75°C, measured zero lead length (Note 2) | 1 |
| Derate Above 75°C (lead-measured) |  |  | 25 |  | mW/°C | above 75°C | 1 |
| DC Power Dissipation (ambient) | PD |  |  | 0.55 | W | @ TA = 25°C (Note 3) | 1 |
| Derate Above 25°C (ambient) |  |  | 4.4 |  | mW/°C | above 25°C | 1 |
| Thermal Resistance from Junction-to-Lead | RθJL |  | 40 |  | °C/W |  | 1 |
| Thermal Resistance from Junction-to-Ambient | RθJA |  | 226 |  | °C/W |  | 1 |
| Operating and Storage Temperature Range | TJ, Tstg | -65 |  | 150 | °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: `SZ1SMB75CAT3G`
- Footprint: `Diode_SMD:D_SMB`
- 3D model: SMB (KiCad packages3D, STEP)
- 3D model files: `sz1smb75cat3g-etched.step` / `sz1smb75cat3g-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `sz1smb75cat3g.step` / `sz1smb75cat3g.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Littelfuse datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8588938451818962944) (7 pp, sha256 `b867ff8d1ae59140`, retrieved 2026-10-16, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-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/sz1smb75cat3g-datasheet.pdf)