# BC640

**Changjing** · Bipolar (BJT) · TO-92

BC640 from Changjing, in a TO-92. 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 | EMITTER | passive | Emitter terminal of the PNP transistor; the datasheet limits emitter-base voltage to -5 V and continuous collector current to -1 A. |
| 2 | COLLECTOR | passive | Collector terminal of the PNP transistor; for the BC640 the datasheet limits collector-emitter voltage to -80 V and collector-base voltage to -100 V. |
| 3 | BASE | passive | Base terminal of the PNP transistor; the datasheet specifies VCE(sat) of -0.5 V at IC = -500 mA with IB = -50 mA. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Changjing |
| Package | TO-92 |
| 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-emitter voltage (BC640) | VCEO |  |  | -80 | V | Ta=25℃ | 1 |
| Collector-base voltage (BC640) | VCBO |  |  | -100 | V | Ta=25℃ | 1 |
| Emitter-base voltage | VEBO |  |  | -5 | V | Ta=25℃ | 1 |
| Collector current, continuous | IC |  |  | -1 | A | Ta=25℃ | 1 |
| Collector power dissipation | PC |  |  | 0.83 | W | Ta=25℃ | 1 |
| Operating junction and storage temperature range | TJ,Tstg | -55 |  | 150 | ℃ |  | 1 |
| Thermal resistance, junction to ambient | RӨJA |  |  | 150 | ℃/W |  | 1 |
| Collector-base breakdown voltage (BC640) | V(BR)CBO | -100 |  |  | V | IC=-100μA, IE=0 | 2 |
| Collector-emitter breakdown voltage (BC640) | V(BR)CEO | -80 |  |  | V | IC=-1mA, IB=0 | 2 |
| Emitter-base breakdown voltage | V(BR)EBO | -5 |  |  | V | IE=-100μA, IC=0 | 2 |
| Collector cut-off current | ICBO |  |  | -0.1 | μA | VCB=-30V, IE=0 | 2 |
| Emitter cut-off current | IEBO |  |  | -0.1 | μA | VEB=-5V, IC=0 | 2 |
| DC current gain hFE(1) | hFE(1) | 40 |  |  |  | VCE=-2V, IC=-5mA | 2 |
| DC current gain hFE(2) | hFE(2) | 63 |  | 250 |  | VCE=-2V, IC=-150mA | 2 |
| DC current gain hFE(3) | hFE(3) | 25 |  |  |  | VCE=-2V, IC=-500mA | 2 |
| Collector-emitter saturation voltage | VCE(sat) |  |  | -0.5 | V | IC=-500mA, IB=-50mA | 2 |
| Base-emitter voltage | VBE |  |  | -1 | V | VCE=-2V, IC=-500mA | 2 |
| Transition frequency | fT | 100 |  |  | MHz | VCE=-5V, IC=-50mA, f=100MHz | 2 |

## CAD (KiCad official)

- Symbol: `BC640`
- Footprint: `Package_TO_SOT_THT:TO-92_Inline`
- 3D model: TO-92 (KiCad packages3D, STEP)
- 3D model files: `bc640-etched.step` / `bc640-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `bc640.step` / `bc640.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/8590229271210848256) (4 pp, sha256 `e9614c71cd5ead0d`, retrieved 2026-10-19, 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/bc640-datasheet.pdf)