# TPSMB18A

**Littelfuse** · TVS · DO-214AA

TPSMB18A from Littelfuse, in a DO-214AA. 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 unidirectional TVS (marked by the color band), connected to the protected line, with VR 15.3 V stand-off and VBR 17.1 V typ (15.3-18.9 V min/max band at 1 mA) for TPSMB18A. |
| 2 | Anode | passive | Anode terminal of the unidirectional TVS, normally connected to ground, with maximum clamping voltage VC 25.5 V at Ipp 24.2 A for TPSMB18A. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Littelfuse |
| Package | DO-214AA |
| 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 |
|---|---|---|---|---|---|---|---|
| Breakdown Voltage | VBR | 15.3 |  | 18.9 | V | @ IT = 1 mA | 2 |
| Reverse Stand-off Voltage | VR |  | 15.3 |  | V |  | 2 |
| Maximum Clamping Voltage | VC |  |  | 25.5 | V | @ Ipp = 24.2 A | 2 |
| Maximum Peak Pulse Current | Ipp |  |  | 24.2 | A |  | 2 |
| Maximum Reverse Leakage Current | IR |  |  | 1 | µA | @ VR | 2 |
| Maximum Temperature Coefficient of VBR | αT |  |  | 0.083 | %/C |  | 2 |
| Typical IR at 150°C | IR |  | 8 |  | µA | @150°C | 2 |
| Maximum Instantaneous Forward Voltage | VF |  |  | 3.5 | V | at 50A, unidirectional only, VBR<300V | 1 |
| Peak Pulse Power Dissipation | PPPM |  |  | 600 | W | 10/1000µs waveform | 1 |
| Power Dissipation on infinite heat sink | PM(AV) |  |  | 5 | W | TL=50°C | 1 |
| Peak Forward Surge Current | IFSM |  |  | 100 | A | 8.3ms single half sine wave, unidirectional only | 1 |
| Operating Junction Temperature Range | TJ | -65 |  | 175 | °C | VBR≤91V | 1 |
| Storage Temperature Range | TSTG | -65 |  | 175 | °C |  | 1 |
| Thermal Resistance Junction to Lead | RθJL |  | 20 |  | °C/W | Typical | 1 |
| Thermal Resistance Junction to Ambient | RθJA |  | 100 |  | °C/W | Typical | 1 |
| VBR Voltage Tolerance |  | -5 |  | 5 | % | 5% VBR voltage tolerance (A suffix) | 6 |

## 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 | seconds at terminals • Matte tin lead-free plated | 1 |

## CAD (KiCad official)

- Symbol: `TPSMB18A`
- Footprint: `Diode_SMD:D_SMB`
- 3D model: DO-214AA (KiCad packages3D, STEP)
- 3D model files: `tpsmb18a-etched.step` / `tpsmb18a-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `tpsmb18a.step` / `tpsmb18a.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Littelfuse datasheet](docs/tpsmb18a-datasheet.pdf) (6 pp, sha256 `0ac950ffb3161f3d`, 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/tpsmb18a-datasheet.pdf)