# MJD31CT4

**STMicroelectronics** · Bipolar (BJT) · DPAK

MJD31CT4 from STMicroelectronics, in a DPAK. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

## Pinout

| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | B | input | Base control terminal with absolute maximum input current rating of 1 A for controlling collector current. |
| 2 | C | output | Collector terminal with TAB providing thermal connection, rated for maximum 3 A continuous current and 100 V collector-emitter voltage. |
| 3 | E | output | Emitter terminal providing the return current path for this NPN power transistor. |

## Key specifications

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

## CAD (KiCad official)

- Symbol: `MJD31CT4`
- Footprint: `Package_TO_SOT_SMD:TO-252-2`
- 3D model: DPAK (KiCad packages3D, STEP)
- 3D model files: `mjd31ct4-etched.step` / `mjd31ct4-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `mjd31ct4.step` / `mjd31ct4.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/mjd31ct4.pdf) (13 pp, sha256 `339d9033aceba953`, retrieved 2026-09-22, tier: manufacturer)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.2`, primary `claude-haiku-4-5-20251001` (text), consensus `claude-sonnet-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/mjd31ct4-datasheet.pdf)