# SZ1SMB14AT3G

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

SZ1SMB14AT3G 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 | Cathode terminal of the uni-directional TVS, identified by the cathode mark and color band on the package; the device is rated for a working peak reverse voltage VRWM of 14 V with a minimum breakdown voltage VBR of 15.6 V. |
| 2 | Anode | passive | Anode terminal of the uni-directional TVS, opposite the cathode mark; the device clamps transients at 23.2 V at a peak pulse current of 25.8 A per the electrical characteristics. |

## 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 | VBR | 15.6 | 16.4 | 17.2 | V | @ IT = 1.0 mA (Note 7) | 3 |
| Maximum reverse leakage current | IR |  |  | 5 | µA | @ VRWM | 3 |
| Clamping voltage | VC |  |  | 23.2 | V | @ IPP = 25.8 A (Note 8) | 3 |
| Forward voltage | VF |  |  | 3.5 | V | @ IF = 30 A (Note 5), uni-directional | 2 |
| Peak power dissipation | PPK |  |  | 600 | W | TL = 25°C, pulse width = 1 ms (Note 1) | 1 |
| DC power dissipation, measured zero lead length | PD |  |  | 3 | W | TL = 75°C (Note 2) | 1 |
| DC power dissipation | PD |  |  | 0.55 | W | TA = 25°C (Note 3) | 1 |
| Forward surge current | IFSM |  |  | 100 | A | TA = 25°C, 1/2 sine wave PW = 8.3 ms (Note 4), unidirectional only | 1 |
| Operating and storage temperature range | TJ, Tstg | -65 |  | 150 | °C |  | 1 |
| Working peak reverse voltage | VRWM |  | 14 |  | V | (Note 6) | 3 |
| Typical junction capacitance | C |  | 1085 |  | pF | Bias voltage = 0 V, F = 1 MHz, TJ = 25°C (Note 9) | 3 |
| Thermal resistance, junction-to-lead | RθJL |  | 40 |  | °C/W | Measured zero lead length (Note 2) | 1 |
| Thermal resistance, junction-to-ambient | RθJA |  | 226 |  | °C/W | FR-4 board, Littelfuse minimum recommended footprint (Note 3) | 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: `SZ1SMB14AT3G`
- Footprint: `Diode_SMD:D_SMB`
- 3D model: SMB (KiCad packages3D, STEP)
- 3D model files: `sz1smb14at3g-etched.step` / `sz1smb14at3g-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `sz1smb14at3g.step` / `sz1smb14at3g.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/8588939018747068416) (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/sz1smb14at3g-datasheet.pdf)