# BU406D

**OSEN** · Bipolar (BJT) · TO-252

BU406D from OSEN, in a TO-252. 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 | B | input | Base of the NPN transistor; Emitter-Base voltage max 9 V and continuous base current max 4 A. |
| 2 | C | passive | Collector of the NPN transistor (also the tab); VCBO 400 V, VCEO 200 V, continuous collector current 7 A. |
| 3 | E | passive | Emitter of the NPN transistor; VEBO 9 V max with respect to base. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | OSEN |
| Package | TO-252 |
| Category | Transistors/Thyristors |
| Pins | 3 |

## Electrical characteristics

Limits as printed in the datasheet (page.json `metadata.characteristics` carries them as data).

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Collector Cutoff Current | ICBO |  |  | 10 | uA | VCB=400V, IB=0 | 3 |
| Emitter Cutoff Current | IEBO |  |  | 10 | uA | VEB=9V, IC=0 | 3 |
| Collector Emitter Sustaining voltage (Note 1) | BVCEO | 200 |  |  | V | IC=100mA, IB=0 | 3 |
| Collector Emitter Saturation Voltage (Note 1) | VCE(sat) |  |  | 1 | V | IC=5A,IB=1A | 3 |
| Base-Emitter Saturation Voltage (Note 1) | VBE(sat) |  |  | 1.5 | V | IC=2A,IB=0.4A | 3 |
| DC Current Gain (Note 1) | hFE | 50 |  | 85 |  | IC=2A, VCE=5V | 3 |
| Current-Gain-Bandwidth | fT | 10 |  |  | MHZ | VCE=10V, Ic=0.5A, f=1MHz | 3 |
| Storage Time | Ts | 1 |  | 2.5 | us |  | 3 |
| Rise Time | Tr |  |  | 1 | us | Ic=500mA,UI9600 | 3 |
| Fall Time | Tf |  |  | 1 | us |  | 3 |
| Collector-Base Voltage | VCBO |  |  | 400 | V | Tc=25°C | 2 |
| Collector-Emitter Voltage | VCEO |  |  | 200 | V | Tc=25°C | 2 |
| Emitter-Base Voltage | VEBO |  |  | 9 | V | Tc=25°C | 2 |
| Collector Current-Continuous | IC |  |  | 7 | A | Tc=25°C | 2 |
| Base Current-Continuous | IB |  |  | 4 | A | Tc=25°C | 2 |
| Collector Power Dissipation | PC |  |  | 60 | W | Tc=25°C | 2 |
| Max. Operating Junction Temperature | Tj |  |  | 150 | ℃ |  | 2 |
| Storage Temperature | Tstg | -55 |  | 150 | ℃ |  | 2 |
| Junction to Case Thermal Resistance | θJC |  | 2.08 |  | °C/W |  | 2 |

## CAD (KiCad official)

- Symbol: `BU406D`
- Footprint: `Package_TO_SOT_SMD:TO-252-2`
- 3D model: TO-252 (KiCad packages3D, STEP)
- 3D model files: `bu406d-etched.step` / `bu406d-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `bu406d.step` / `bu406d.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [OSEN datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8603502962438524928) (3 pp, sha256 `1ebef8ffc6a6d215`, retrieved 2026-10-19, tier: lcsc)
- **Datasheet language:** Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
- **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/bu406d-datasheet.pdf)