# TPSMB550A-A

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

TPSMB550A-A 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, marked by the color/cathode band on the unidirectional TPSMB550A-A, which is the end connected to the positive side of the protected line (reverse stand-off VR 468V, breakdown VBR 522.5V typ. nominal at 1mA). |
| 2 | Anode | passive | Anode terminal of the unidirectional TPSMB550A-A, connected to the return/ground side of the protected line (600W peak pulse power at 10/1000µs). |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Littelfuse |
| Package | DO-214AA |
| 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 | 522.5 |  | 577.5 | V | @ IT = 1 mA | 2 |
| Reverse Stand-off Voltage | VR |  | 468 |  | V |  | 2 |
| Maximum Clamping Voltage | VC |  |  | 760 | V | @ Ipp = 0.8 A | 2 |
| Maximum Peak Pulse Current | Ipp |  |  | 0.8 | A |  | 2 |
| Maximum Reverse Leakage | IR |  |  | 1 | µA | @ VR | 2 |
| Maximum Instantaneous Forward Voltage (Unidirectional) | VF |  |  | 5 | V | at 50A | 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 (VBR > 91V) | TJ | -65 |  | 150 | °C | VBR > 91V | 1 |
| Storage Temperature Range | TSTG | -65 |  | 175 | °C |  | 1 |
| Temperature coefficient of VBR | αT |  |  | 0.112 | %/C | Maximum | 2 |
| Typical Reverse Leakage at 150°C | IR |  | 8 |  | µA | @150°C | 2 |
| Thermal Resistance Junction to Lead | RƟJL |  | 20 |  | °C/W | Typical | 1 |
| Thermal Resistance Junction to Ambient | RƟJA |  | 100 |  | °C/W | Typical | 1 |
| VBR Voltage Tolerance |  | -5 |  | 5 | % | A suffix: 5% VBR voltage tolerance | 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: `TPSMB550A-A`
- Footprint: `Diode_SMD:D_SMB`
- 3D model: DO-214AA (KiCad packages3D, STEP)
- 3D model files: `tpsmb550a-a-etched.step` / `tpsmb550a-a-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `tpsmb550a-a.step` / `tpsmb550a-a.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Littelfuse datasheet](docs/tpsmb550a-a-datasheet.pdf) (6 pp, sha256 `0ac950ffb3161f3d`, retrieved 2026-10-27, 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/tpsmb550a-a-datasheet.pdf)