# BC556B

**LGE** · Bipolar (BJT) · TO-92

BC556B from LGE, 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 device; the emitter-base voltage rating is VEBO = -5 V and the continuous collector current rating is -100 mA. |
| 2 | BASE | passive | Base terminal; base-emitter saturation voltage VBE(sat) is -1 V max at IC = -100 mA, IB = -5 mA. |
| 3 | COLLECTOR | passive | Collector terminal; rated up to VCBO = -80 V (BC556), VCEO = -65 V (BC556), IC = -100 mA continuous, and PC = 625 mW. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | LGE |
| 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-base breakdown voltage (BC556) | VCBO | -80 |  |  | V | IC= -100μA, IE=0 | 1 |
| Collector-emitter breakdown voltage (BC556) | VCEO | -65 |  |  | V | IC= -2mA, IB=0 | 1 |
| Emitter-base breakdown voltage | VEBO | -5 |  |  | V | IE= -100μA, IC=0 | 1 |
| Collector cut-off current (BC556) | ICBO |  |  | -0.1 | μA | VCB=-70 V, IE=0 | 1 |
| Emitter cut-off current (BC556) | IEBO |  |  | -0.1 | μA | VEB= -5 V, IC=0 | 1 |
| DC current gain (BC556B/BC557B/BC558B) | hFE | 180 |  | 460 |  | VCE=-5V, IC= -2mA | 1 |
| Collector-emitter saturation voltage | VCE(sat) |  |  | -0.65 | V | IC=-100mA, IB= -5mA | 1 |
| Base-emitter saturation voltage | VBE(sat) |  |  | -1 | V | IC= -100mA, IB=-5mA | 1 |
| Transition frequency | fT |  | 150 |  | MHz | VCE= -5V, IC= -10mA, f = 100MHz | 1 |
| Collector-base voltage (BC556) | VCBO |  |  | -80 | V |  | 1 |
| Collector-emitter voltage (BC556) | VCEO |  |  | -65 | V |  | 1 |
| Emitter-base voltage | VEBO |  |  | -5 | V |  | 1 |
| Collector current, continuous | IC |  |  | -100 | mA |  | 1 |
| Collector power dissipation | PC |  |  | 625 | mW |  | 1 |
| Junction temperature | TJ |  |  | 150 | ℃ |  | 1 |
| Storage temperature | Tstg | -55 |  | 150 | ℃ |  | 1 |

## CAD (KiCad official)

- Symbol: `BC556B`
- Footprint: `Package_TO_SOT_THT:TO-92_Inline`
- 3D model: TO-92 (KiCad packages3D, STEP)
- 3D model files: `bc556b-etched.step` / `bc556b-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `bc556b.step` / `bc556b.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [LGE datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8588892868118761472) (4 pp, sha256 `3f07b60d7056ca34`, 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/bc556b-datasheet.pdf)