# MJD127T4

**STMicroelectronics** · Darlington Transistors · TO-252-2(DPAK)

MJD127T4 from STMicroelectronics, in a TO-252-2(DPAK). 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 input terminal of PNP Darlington transistor; maximum base current 120 mA, maximum emitter-base voltage 5 V. |
| 2 | C | passive | Collector terminal with thermal connection tab; rated for 100 V collector-emitter voltage, 8 A continuous collector current, with integrated antiparallel diode. |
| 3 | E | passive | Emitter terminal; completes the main current path through the monolithic Darlington pair configuration. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | STMicroelectronics |
| Package | TO-252-2(DPAK) |
| Category | Transistors/Thyristors |
| Pins | 3 |

## CAD (KiCad official)

- Symbol: `MJD127T4`
- Footprint: `Package_TO_SOT_SMD:TO-252-2`
- 3D model: TO-252-2(DPAK) (KiCad packages3D, STEP)
- 3D model files: `mjd127t4-etched.step` / `mjd127t4-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `mjd127t4.step` / `mjd127t4.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/mjd127t4.pdf) (15 pp, sha256 `f47b5fb35fecff32`, retrieved 2026-10-06, tier: manufacturer)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-4-5-20251001` (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/mjd127t4-datasheet.pdf)