# SZ1SMB24AT3G

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

SZ1SMB24AT3G 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 | K | passive | Cathode: the banded/marked end per the datasheet; pad 1 of the KiCad diode footprint. |
| 2 | A | passive | Anode. |

## 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 | VBR | 26.7 | 28.1 | 29.5 | V | @ IT = 1.0 mA; TA = 25°C (Note 7) | 3 |
| Peak Power Dissipation | PPK |  |  | 600 | W | TL = 25°C, pulse width = 1 ms (Note 1: 10/1000 µs, non-repetitive) | 1 |
| DC Power Dissipation (measured zero lead length) | PD |  |  | 3 | W | TL = 75°C (Note 2) | 1 |
| DC Power Dissipation (FR-4 minimum footprint) | 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, 4 pulses per minute max (Note 4, unidirectional only) | 1 |
| Operating and Storage Temperature Range | TJ, Tstg | -65 |  | 150 | °C |  | 1 |
| Reverse Leakage Current | IR |  | 5 |  | µA | @ VRWM = 24 V | 3 |
| Clamping Voltage | VC |  | 38.9 |  | V | @ IPP = 15.4 A (Note 8: surge per Figure 1) | 3 |
| Maximum Reverse Peak Pulse Current | IPP |  | 15.4 |  | A | Note 8: surge current waveform per Figure 1 | 3 |
| Working Peak Reverse Voltage | VRWM |  | 24 |  | V |  | 3 |
| Junction Capacitance | C |  | 675 |  | pF | Bias = 0 V, F = 1 MHz, TJ = 25°C (Note 9) | 3 |
| DC Power Derating above 75°C |  |  | 40 |  | mW/°C | Derate above TL = 75°C | 1 |
| Thermal Resistance Junction-to-Lead | RƟJL |  | 25 |  | °C/W | Measured zero lead length (Note 2) | 1 |
| DC Power Derating above 25°C |  |  | 4.4 |  | mW/°C | Derate above TA = 25°C (Note 3) | 1 |
| Thermal Resistance Junction-to-Ambient | RƟJL |  | 226 |  | °C/W | FR-4 board, Littelfuse minimum recommended footprint (Note 3) | 1 |

## CAD (KiCad official)

- Symbol: `SZ1SMB24AT3G`
- Footprint: `Diode_SMD:D_SMB`
- 3D model: SMB (KiCad packages3D, STEP)
- 3D model files: `sz1smb24at3g-etched.step` / `sz1smb24at3g-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `sz1smb24at3g.step` / `sz1smb24at3g.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/8588903844030402561) (8 pp, sha256 `c6158fa7c0646329`, retrieved 2026-10-15, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins`, primary `cathode-band convention` (convention), consensus `off` (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/sz1smb24at3g-datasheet.pdf)