# SMBJ40AQ

**Yangzhou Yangjie Elec Tech** · ESD And Surge Protection (TVS/ESD) · SMB

SMBJ40AQ from Yangzhou Yangjie Elec Tech, in a SMB. 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 end marked with the band on uni-directional SMBJ40AQ; connect to the protected line, with working peak reverse voltage 40 V and breakdown 44.4 V to 49.1 V at 1 mA. |
| 2 | A | passive | Anode, the unbanded end of the uni-directional SMBJ40AQ; connect to ground, with maximum clamping voltage 64.5 V at 9.3 A peak pulse current. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Yangzhou Yangjie Elec Tech |
| Package | SMB |
| 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 | 44.4 |  | 49.1 | V | @ IT = 1 mA | 2 |
| Working Peak Reverse Voltage | VRWM |  | 40 |  | V |  | 2 |
| Maximum Reverse Leakage | IR |  |  | 1 | μA | @ VRWM | 2 |
| Maximum Reverse Surge Current | IPP |  |  | 9.3 | A |  | 2 |
| Maximum Clamping Voltage | Vc |  |  | 64.5 | V | @ IPP | 2 |
| Maximum instantaneous forward voltage | VF |  |  | 3.5 | V | at 50A, unidirectional only | 1 |
| Peak pulse power dissipation | PPPM |  |  | 600 | W | 10/1000us waveform | 1 |
| Power dissipation | PD |  |  | 5 | W | on infinite heat sink at TL=75℃ | 1 |
| Peak forward surge current | IFSM |  |  | 100 | A | 8.3 ms single half sine-wave, unidirectional only | 1 |
| Operating junction temperature | TJ | -55 |  | 175 | ℃ |  | 1 |
| Storage temperature range | TSTG | -55 |  | 175 | ℃ |  | 1 |
| Thermal resistance junction to lead | RθJL |  | 20 |  | ℃/W | junction to lead | 3 |
| Thermal resistance junction to ambient | RθJA |  | 100 |  | ℃/W | junction to ambient | 3 |

## 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 |
|---|---|---|---|---|
| housing |  | black | 4. Body color: Black | 3 |
| contacts |  | tin | ● Terminals: Matte tin plated leads, solderable per J-STD-002 and JESD22-B102 | 1 |

## CAD (KiCad official)

- Symbol: `SMBJ40AQ`
- Footprint: `Diode_SMD:D_SMB`
- 3D model: SMB (KiCad packages3D, STEP)
- 3D model files: `smbj40aq-etched.step` / `smbj40aq-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `smbj40aq.step` / `smbj40aq.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Yangzhou Yangjie Elec Tech datasheet](docs/smbj40aq-datasheet.pdf) (6 pp, sha256 `c858e6d6adc08fc3`, 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/smbj40aq-datasheet.pdf)