# SMDJ78A

**Brightking Elec (TAIWAN)** · TVS · SMC(DO-214AB)

SMDJ78A from Brightking Elec (TAIWAN), in a SMC(DO-214AB). 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 color band), reverse stand-off voltage VRWM 78V, breakdown 86.70~95.80V at 1mA, max clamping 126V at 23.8A. |
| 2 | A | passive | Anode terminal of the unidirectional TVS, opposite the cathode band; forward surge current IFSM is 300A (8.3ms half sine-wave). |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Brightking Elec (TAIWAN) |
| Package | SMC(DO-214AB) |
| 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 |
|---|---|---|---|---|---|---|---|
| Reverse Stand-Off Voltage | VRWM |  | 78 |  | V |  | 3 |
| Breakdown Voltage | VBR | 86.7 |  | 95.8 | V | @IT=1 mA | 3 |
| Test Current | IT |  | 1 |  | mA |  | 3 |
| Maximum Clamping Voltage | VC |  |  | 126 | V | @IPP=23.8 A | 3 |
| Peak Pulse Current | IPP |  |  | 23.8 | A | 10/1000μs waveform | 3 |
| Reverse Leakage | IR |  |  | 2 | μA | @VRWM | 3 |
| Peak pulse power dissipation | PPPM | 3000 |  |  | W | 10/1000μs waveform, TA=25℃ | 1 |
| Steady state power dissipation | PM(AV) |  |  | 6.5 | W | TA=50℃ | 1 |
| Peak forward surge current | IFSM |  |  | 300 | A | 8.3ms single half sine-wave, JEDEC method | 1 |
| Operating junction and storage temperature | TJ,TSTG | -55 |  | 150 | ℃ |  | 1 |
| Thermal resistance junction to lead | RθJL |  | 15 |  | ℃/W | Typical | 1 |
| Thermal resistance junction to ambient | RθJA |  | 75 |  | ℃/W | Typical | 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 | copper |  | 2. Mounted on 8.0mm×8.0mm copper pads to each terminal. | 1 |

## CAD (KiCad official)

- Symbol: `SMDJ78A`
- Footprint: `Diode_SMD:D_SMC`
- 3D model: SMC(DO-214AB) (KiCad packages3D, STEP)
- 3D model files: `smdj78a-etched.step` / `smdj78a-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `smdj78a.step` / `smdj78a.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Brightking Elec (TAIWAN) datasheet](docs/smdj78a-datasheet.pdf) (6 pp, sha256 `ca25bd05b5281e29`, 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/smdj78a-datasheet.pdf)