# BUL49D

**STMicroelectronics** · Bipolar (BJT) · TO-220

BUL49D from STMicroelectronics, in a TO-220. 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 terminal of the NPN power transistor; base current IB is rated up to 2 A continuous and 4 A peak (tP < 5 ms). |
| 2 | C | passive | Collector terminal of the NPN power transistor; collector-emitter voltage VCES (VBE=0) is rated up to 850 V and collector current IC up to 5 A (10 A peak, tP < 5 ms). |
| 3 | E | passive | Emitter terminal of the NPN power transistor, internally connected to an integral flyback (freewheeling) diode; emitter-base breakdown voltage V(BR)EBO is 10 to 18 V. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | STMicroelectronics |
| Package | TO-220 |
| Category | Transistors/Thyristors |
| Pins | 3 |

## CAD (KiCad official)

- Symbol: `BUL49D`
- Footprint: `Package_TO_SOT_THT:TO-220-3_Vertical`
- 3D model: TO-220 (KiCad packages3D, STEP)
- 3D model files: `bul49d-etched.step` / `bul49d-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `bul49d.step` / `bul49d.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [STMicroelectronics datasheet](https://www.st.com/resource/en/datasheet/bul49d.pdf) (15 pp, sha256 `415eee02a8ac53f9`, retrieved 2026-09-24, tier: manufacturer)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.2`, primary `claude-sonnet-5` (text+vision), consensus `claude-opus-4-8` (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/bul49d-datasheet.pdf)