# SZSMF12AT1G

**Littelfuse** · TVS · SOD-123F

SZSMF12AT1G from Littelfuse, in a SOD-123F. 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 of the unidirectional TVS diode, marked by the polarity band and oriented toward the tape sprocket holes; connect to the protected positive line (VRWM 12 V for SZSMF12AT1G). |
| 2 | Anode | passive | Anode of the unidirectional TVS diode, normally connected to ground/return of the protected line. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Littelfuse |
| Package | SOD-123F |
| Category | TVS/Fuse/Board Level 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 |  | 12 |  | V |  | 2 |
| Breakdown Voltage | VBR | 13.3 | 14 | 14.7 | V | @ IT = 1 mA, TA = 25°C | 2 |
| Maximum Reverse Leakage Current | IR |  |  | 2.5 | µA | @ VRWM | 2 |
| Maximum Clamping Voltage | VC |  |  | 19.9 | V | @ IPP | 2 |
| Maximum Reverse Peak Pulse Current | IPP |  |  | 10.1 | A | Surge waveform per Figure 2 | 2 |
| Forward Voltage | VF |  |  | 3.5 | V | IF = 12 A, TA = 25°C | 2 |
| Peak Power Dissipation 10/1000 µs | PPK |  |  | 200 | W | PW-10/1000 µs, non-repetitive, TA = 25°C | 1 |
| Peak Power Dissipation 8/20 µs | PPK |  |  | 1000 | W | TA = 25°C, PW-8/20 µs | 1 |
| DC Power Dissipation | PD |  |  | 385 | mW | TA = 25°C, FR-4 min pad | 1 |
| Power Derating above 25°C |  |  |  | 4 | mW/°C | Derate above 25°C | 1 |
| Thermal Resistance Junction-to-Ambient | RθJA |  |  | 325 | °C/W | Mounted with recommended minimum pad, FR-4 | 1 |
| Thermal Resistance Junction-to-Lead | RθJL |  |  | 26 | °C/W | Mounted with recommended minimum pad, FR-4 | 1 |
| Operating and Storage Temperature Range | TJ, Tstg | -55 |  | 150 | °C |  | 1 |
| Breakdown Test Current | IT |  | 1 |  | mA | VBR measured at TA = 25°C | 2 |

## 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 | Terminal Matte Tin-plated leads, Solderable per JESD22-B102 | 4 |

## CAD (KiCad official)

- Symbol: `SZSMF12AT1G`
- Footprint: `Diode_SMD:D_SOD-123F`
- 3D model: SOD-123F (KiCad packages3D, STEP)
- 3D model files: `szsmf12at1g-etched.step` / `szsmf12at1g-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `szsmf12at1g.step` / `szsmf12at1g.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Littelfuse datasheet](docs/szsmf12at1g-datasheet.pdf) (6 pp, sha256 `c7f007045647a940`, retrieved 2026-10-22, 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/szsmf12at1g-datasheet.pdf)