# 2SC4944

**Changjing** · Bipolar (BJT) · SOT-353

2SC4944 from Changjing, in a SOT-353. 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 | B1 | input | Base of the first NPN transistor (the one whose collector is pin 5); VEBO max 5 V. |
| 2 | E | passive | Common emitter of both NPN transistors; collector current is 150 mA max per the ratings. |
| 3 | B2 | input | Base of the second NPN transistor (the one whose collector is pin 4); VEBO max 5 V. |
| 4 | C2 | passive | Collector of the second NPN transistor; VCBO 60 V, VCEO 50 V, IC 150 mA continuous. |
| 5 | C1 | passive | Collector of the first NPN transistor; VCBO 60 V, VCEO 50 V, IC 150 mA continuous. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Changjing |
| Package | SOT-353 |
| Category | Transistors/Thyristors |
| Pins | 5 |

## 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 Voltage | VCBO |  |  | 60 | V |  | 1 |
| Collector-Emitter Voltage | VCEO |  |  | 50 | V |  | 1 |
| Emitter-Base Voltage | VEBO |  |  | 5 | V |  | 1 |
| Collector Current -Continuous | IC |  |  | 150 | mA |  | 1 |
| Collector Power Dissipation | PC |  |  | 200 | mW |  | 1 |
| Operation Junction and Storage Temperature Range | TJ,Tstg | -55 |  | 150 | ℃ |  | 1 |
| Collector-base breakdown voltage | V(BR)CBO | 60 |  |  | V | IC=100μA,IE=0 | 1 |
| Collector-emitter breakdown voltage | V(BR)CEO | 50 |  |  | V | IC=1mA,IB=0 | 1 |
| Emitter-base breakdown voltage | V(BR)EBO | 5 |  |  | V | IE=100μA,IC=0 | 1 |
| Collector cut-off current | ICBO |  |  | 0.1 | μA | VCB=60V,IE=0 | 1 |
| Emitter cut-off current | IEBO |  |  | 0.1 | μA | VEB=5V,IC=0 | 1 |
| DC current gain | hFE | 120 |  | 400 |  | VCE=6V,IC=2mA | 1 |
| Collector-emitter saturation voltage | VCE(sat) |  |  | 0.25 | V | IC=100mA,IB=10mA | 1 |

## CAD (KiCad official)

- Symbol: `2SC4944`
- Footprint: `Package_TO_SOT_SMD:SOT-353_SC-70-5`
- 3D model: SOT-353 (KiCad packages3D, STEP)
- 3D model files: `2sc4944-etched.step` / `2sc4944-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `2sc4944.step` / `2sc4944.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/8590919838087139328) (3 pp, sha256 `94c555b7567e292d`, retrieved 2026-10-21, tier: lcsc)
- **Extractor:** `ds2sf` (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
- **CAD:** KiCad official libraries (CC-BY-SA 4.0).

[Datasheet PDF](docs/2sc4944-datasheet.pdf)