# TPSMF4L78A

**Littelfuse** · ESD And Surge Protection (TVS/ESD) · SOD-123FL

TPSMF4L78A from Littelfuse, in a SOD-123FL. 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 of the uni-directional TVS diode, marked by the color band, connected to the protected line; reverse stand-off voltage VR is 78 V and breakdown voltage VBR is 86.7 V to 95.8 V at 1 mA. |
| 2 | A | passive | Anode of the uni-directional TVS diode, normally connected to ground or the return path; maximum clamping voltage is 126 V at Ipp of 3.2 A. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Littelfuse |
| Package | SOD-123FL |
| Category | Circuit Protection |
| Pins | 2 |

## CAD (KiCad official)

- Symbol: `TPSMF4L78A`
- Footprint: `Diode_SMD:D_SOD-123F`
- 3D model: SOD-123FL (KiCad packages3D, STEP)
- 3D model files: `tpsmf4l78a-etched.step` / `tpsmf4l78a-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `tpsmf4l78a.step` / `tpsmf4l78a.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/8576896659537776640) (6 pp, sha256 `0538aa3240013aeb`, retrieved 2026-10-13, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-sonnet-5-5` (text+vision), consensus `claude-opus-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/tpsmf4l78a-datasheet.pdf)