# MJD31C

**Changjing** · Bipolar (BJT) · TO-252-2L

MJD31C from Changjing, in a TO-252-2L. 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 | BASE | input | Base terminal of the NPN transistor; the datasheet gives no separate base current limit, and the emitter-base breakdown voltage V(BR)EBO is specified at 5 V minimum. |
| 2 | COLLECTOR | passive | Collector terminal of the NPN transistor, rated for a collector-base voltage VCBO of 100 V, a collector-emitter voltage VCEO of 100 V, and continuous collector current IC of 3 A. |
| 3 | EMITTER | passive | Emitter terminal of the NPN transistor, with the emitter-base voltage VEBO rated at 5 V. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Changjing |
| Package | TO-252-2L |
| 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-base breakdown voltage | V(BR)CBO | 100 |  |  | V | IC= 1mA, IE=0 | 1 |
| Collector-emitter breakdown voltage | VCEO(sus) | 100 |  |  | V | IC= 30mA, IB=0 | 1 |
| Emitter-base breakdown voltage | V(BR)EBO | 5 |  |  | V | IE= 1mA, IC=0 | 1 |
| Collector cut-off current | ICES |  |  | 20 | μA | VCE=100V, VEB=0 | 1 |
| Collector cut-off current | ICEO |  |  | 50 | μA | VCE= 60V, IB= 0 | 1 |
| Emitter cut-off current | IEBO |  |  | 1 | mA | VEB=5V, IC=0 | 1 |
| DC current gain | hFE(1) | 25 |  |  |  | VCE= 4V, IC= 1A | 1 |
| DC current gain | hFE(2) | 15 |  | 75 |  | VCE=4 V, IC= 3A | 1 |
| Transition frequency | fT | 3 |  |  | MHZ | VCE=10V , IC=0.5A,fT=1KHz | 1 |
| Collector-emitter saturation voltage | VCE(sat) |  |  | 1.2 | V | IC=3A, IB=0.375A | 1 |
| Base-emitter voltage | VBE(on) |  |  | 1.8 | V | VCE= 4V, IC=3A | 1 |
| Collector-Base Voltage | VCBO |  |  | 100 | V |  | 1 |
| Collector-Emitter Voltage | VCEO |  |  | 100 | V |  | 1 |
| Emitter-Base Voltage | VEBO |  |  | 5 | V |  | 1 |
| Collector Current -Continuous | IC |  |  | 3 | A |  | 1 |
| Collector Power Dissipation | PC |  |  | 1.25 | W |  | 1 |
| Junction Temperature | TJ |  |  | 150 | ℃ |  | 1 |
| Storage Temperature | Tstg | -65 |  | 150 | ℃ |  | 1 |

## CAD (KiCad official)

- Symbol: `MJD31C`
- Footprint: `Package_TO_SOT_SMD:TO-252-2`
- 3D model: TO-252-2L (KiCad packages3D, STEP)
- 3D model files: `mjd31c-etched.step` / `mjd31c-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `mjd31c.step` / `mjd31c.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Changjing datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8586176002301444096) (3 pp, sha256 `943fe0022b98e97a`, retrieved 2026-10-09, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-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/mjd31c-datasheet.pdf)