# SZ1SMA12AT3G

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

SZ1SMA12AT3G from Littelfuse, in a SMA. 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; the color band marks the cathode on unidirectional parts. |
| 2 | Anode | passive | Anode terminal of the uni-directional TVS, opposite the cathode band marking. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Littelfuse |
| Package | SMA |
| 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 | 13.3 | 14 | 14.7 | V | IT = 1 mA | 3 |
| Maximum Reverse Leakage Current | IR |  |  | 2.5 | µA | @ VRWM | 3 |
| Clamping Voltage | VC |  | 19.9 |  | V | IPP = 20.1 A | 3 |
| Typical Junction Capacitance | C |  | 925 |  | pF | Bias voltage = 0 V, F = 1.0 MHz, TJ = 25°C (Note 9) | 3 |
| Forward Voltage | VF |  |  | 3.5 | V | IF = 30 A (Note 5) | 2 |
| Peak Peak Power Dissipation | PPK |  |  | 400 | W | TL = 25°C, Pulse Width = 1 ms (Note 1) | 1 |
| DC Power Dissipation at Lead | PD |  |  | 1.5 | W | TL = 75°C, measured zero lead length (Note 2) | 1 |
| Derating Above 75°C at Lead | PD |  |  | 20 | mW/°C | Derate above TL = 75°C (Note 2) | 1 |
| DC Power Dissipation at Ambient | PD |  |  | 0.5 | W | TA = 25°C (Note 3) | 1 |
| Derating Above 25°C at Ambient | PD |  |  | 4 | mW/°C | Derate above TA = 25°C (Note 3) | 1 |
| Thermal Resistance Junction-to-Lead | RθJL |  |  | 50 | °C/W | Measured zero lead length (Note 2) | 1 |
| Thermal Resistance Junction-to-Ambient | RθJA |  |  | 120 | °C/W | Note 3 | 1 |
| Forward Surge Current | IFSM |  |  | 40 | A | TA = 25°C, 1/2 sine wave PW = 8.3 ms (Note 4), for uni-directional | 1 |
| Operating and Storage Temperature Range | TJ, Tstg | -65 |  | 175 | °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 | the terminal finish material is tin(Sn) (IPC/JEDEC J-STD￾609A.01) | 1 |

## CAD (KiCad official)

- Symbol: `SZ1SMA12AT3G`
- Footprint: `Diode_SMD:D_SMA`
- 3D model: SMA (KiCad packages3D, STEP)
- 3D model files: `sz1sma12at3g-etched.step` / `sz1sma12at3g-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `sz1sma12at3g.step` / `sz1sma12at3g.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/8590386659901534208) (7 pp, sha256 `28d8bdc1607bd94e`, retrieved 2026-10-26, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-5-5` (text), consensus `off` (skipped (clean text read)), 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/sz1sma12at3g-datasheet.pdf)