# 1KSMB56A

**Littelfuse** · ESD And Surge Protection (TVS/ESD) · DO-214AA(SMBJ)

1KSMB56A from Littelfuse, in a DO-214AA(SMBJ). 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 | DO-214AA(SMBJ) |
| 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 (min) | VBR | 53.2 |  | 58.8 | V | @ IT = 1 mA | 2 |
| Maximum clamping voltage | VC |  |  | 77 | V | @ Ipp (13.0 A in this row) | 2 |
| Maximum peak pulse current | Ipp |  |  | 13 | A |  | 2 |
| Maximum reverse leakage current | IR |  |  | 1 | µA | @ VR (47.80 V in this row) | 2 |
| Reverse stand-off voltage | VR |  |  | 47.8 | V |  | 2 |
| Breakdown voltage tolerance (A-suffix part) | VBR | -5 |  | 5 | % | VBR, A-suffix part | 6 |
| Peak pulse power dissipation | PPPM |  |  | 1000 | W | TA=25°C, 10/1000µs waveform (Fig.2) | 1 |
| Power dissipation on infinite heat sink | PD |  |  | 5 | W | TL=50°C | 1 |
| Peak forward surge current | IFSM |  |  | 120 | A | 8.3ms single half sine wave (Note 3) | 1 |
| Maximum instantaneous forward voltage | VF |  |  | 3.5 | V | at 50A, unidirectional only | 1 |
| Operating temperature range | TJ | -65 |  | 150 | °C |  | 1 |
| Storage temperature range | TSTG | -65 |  | 175 | °C |  | 1 |
| Breakdown voltage temperature coefficient | αT |  | 0.1 |  | % | VBR@TJ = VBR@25°C x (1+αT x (TJ-25)) | 1 |
| Thermal resistance junction to lead | RθJL |  | 20 |  | °C/W | junction to lead | 1 |
| Thermal resistance junction to ambient | RθJA |  | 100 |  | °C/W | junction to ambient | 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 | • Matte tin lead-free Plated • Available in breakdown | 1 |

## CAD (KiCad official)

- Symbol: `1KSMB56A`
- Footprint: `Diode_SMD:D_SMB`
- 3D model: DO-214AA(SMBJ) (KiCad packages3D, STEP)
- 3D model files: `1ksmb56a-etched.step` / `1ksmb56a-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `1ksmb56a.step` / `1ksmb56a.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/8589973355399966720) (6 pp, sha256 `5456789e35da8ee5`, retrieved 2026-10-16, 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/1ksmb56a-datasheet.pdf)