# 2SC4618

**Changjing** · Bipolar (BJT) · SOT-523

2SC4618 from Changjing, in a SOT-523. 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 | passive | Base terminal of the NPN transistor, with emitter-base breakdown V(BR)EBO of 5 V minimum at IE=50µA and absolute maximum emitter-base voltage VEBO of 5 V. |
| 2 | EMITTER | passive | Emitter terminal of the NPN transistor, with absolute maximum emitter-base voltage VEBO of 5 V and maximum collector current IC of 50 mA. |
| 3 | COLLECTOR | passive | Collector terminal of the NPN transistor, with absolute maximum collector-base voltage VCBO of 40 V, collector-emitter voltage VCEO of 25 V, and collector current IC of 50 mA. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Changjing |
| Package | SOT-523 |
| 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 | 40 |  |  | V | IC=50µA, IE=0 | 1 |
| Collector-emitter breakdown voltage | V(BR)CEO | 25 |  |  | V | IC=1mA, IB=0 | 1 |
| Emitter-base breakdown voltage | V(BR)EBO | 5 |  |  | V | IE=50µA, IC=0 | 1 |
| Collector cut-off current | ICBO |  |  | 500 | nA | VCB=24V, IE=0 | 1 |
| Emitter cut-off current | IEBO |  |  | 500 | nA | VEB=3V, IC=0 | 1 |
| DC current gain | hFE | 56 |  | 270 |  | VCE=6V, IC=1mA | 1 |
| Collector-emitter saturation voltage | VCE(sat) |  |  | 0.3 | V | IC=10mA, IB=1mA | 1 |
| Transition frequency | fT | 150 |  |  | MHz | VCE=6V, IC=1mA, f=100MHz | 1 |
| Collector output capacitance | Cob |  |  | 2.2 | pF | VCB=6V, IE=0, f=1MHz | 1 |
| Collector-Base Voltage | VCBO |  |  | 40 | V |  | 1 |
| Collector-Emitter Voltage | VCEO |  |  | 25 | V |  | 1 |
| Emitter-Base Voltage | VEBO |  |  | 5 | V |  | 1 |
| Collector Current | IC |  |  | 50 | mA |  | 1 |
| Collector Power Dissipation | PC |  |  | 150 | mW |  | 1 |
| Operation Junction and Storage Temperature Range | TJ,Tstg | -55 |  | 150 | ℃ |  | 1 |
| Thermal Resistance From Junction To Ambient | RΘJA |  |  | 833 | ℃/W |  | 1 |

## CAD (KiCad official)

- Symbol: `2SC4618`
- Footprint: `Package_TO_SOT_SMD:SOT-523`
- 3D model: SOT-523, generated from the KiCad footprint (body from the F.Fab outline, terminals on the pads, 0.8 mm nominal SOT-523 height). Neither the vendor nor KiCad ships a 3D model for this package, so the dimensions are nominal, not the manufacturer's CAD (STEP)
- 3D model files: `2sc4618-etched.step` / `2sc4618-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `2sc4618.step` / `2sc4618.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/8590917921122304000) (4 pp, sha256 `b47049dc47205db9`, retrieved 2026-10-18, 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/2sc4618-datasheet.pdf)