# BC546B

**YFW** · Bipolar (BJT) · TO-92

BC546B from YFW, 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 | C | passive | Collector; BVCEO 65V for BC546, IC max 100 mA. |
| 2 | B | passive | Base; BVEBO 6V for BC546/547, hFE 200-450 for the B class at VCE=5V, IC=2mA. |
| 3 | E | passive | Emitter; connect to the most negative node (NPN), total power dissipation 500 mW. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | YFW |
| 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 Voltage (BC546 column) | BVCBO |  |  | 80 | V |  | 1 |
| Collector-Emitter Voltage (BC546 column) | BVCEO |  |  | 65 | V |  | 1 |
| Emitter-Base Voltage (BC546/547 column) | BVEBO |  |  | 6 | V |  | 1 |
| Collector Current | IC |  |  | 100 | mA |  | 1 |
| Collector Power Dissipation | PC |  |  | 500 | mW |  | 1 |
| Junction Temperature | Tj |  |  | 150 | °C |  | 1 |
| Storage Temperature | Tstg | -55 |  | 150 | °C |  | 1 |
| Collector cut-off current | ICBO |  |  | 15 | nA | VCB = 30V, IE = 0 | 1 |
| Emitter cut-off current | IEBO |  |  | 15 | nA | VEB = 5V, IC = 0 | 1 |
| DC current gain (grade B, 200-450) | hFE | 200 |  | 450 |  | VCE = 5V, IC = 2mA | 1 |
| Collector-emitter saturation voltage | VCE(sat) |  |  | 0.25 | V | IC = 10mA, IB = 0.5mA | 1 |
| Collector-emitter saturation voltage | VCE(sat) |  |  | 0.6 | V | IC = 100mA, IB = 5mA | 1 |
| Base-emitter saturation voltage | VBE(sat) |  |  | 1 | V | IC = 100mA, IB = 5mA | 1 |
| Transition frequency | fT |  | 200 |  | MHz | VCE = 5V, IB = 10mA | 1 |
| Collector output capacitance | Cob |  |  | 6 | pF | VCB=10V, IE=0, f=1MHz | 1 |

## CAD (KiCad official)

- Symbol: `BC546B`
- Footprint: `Package_TO_SOT_THT:TO-92_Inline`
- 3D model: TO-92 (KiCad packages3D, STEP)
- 3D model files: `bc546b-etched.step` / `bc546b-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `bc546b.step` / `bc546b.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [YFW datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8603346070881644544) (3 pp, sha256 `0cef28b9533d14be`, retrieved 2026-10-19, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-sonnet-5-5` (text+vision), consensus `claude-opus-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/bc546b-datasheet.pdf)