# BC850B

**Nexperia** · Bipolar (BJT) · SOT-23

BC850B from Nexperia, in a SOT-23. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

## Pinout

| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | B | input | Base control input terminal with maximum peak base current of 200 mA. |
| 2 | E | passive | Emitter terminal providing the common current path for the NPN transistor. |
| 3 | C | output | Collector terminal rated for maximum collector current of 100 mA and maximum collector-emitter voltage of 45 V. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Nexperia |
| Package | SOT-23 |
| 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 | VCBO |  |  | 50 | V | open emitter | 2 |
| collector-emitter voltage | VCEO |  |  | 45 | V | open base | 2 |
| emitter-base voltage | VEBO |  |  | 5 | V | open collector | 2 |
| collector current | IC |  |  | 100 | mA |  | 2 |
| peak collector current | ICM |  |  | 200 | mA |  | 2 |
| peak base current | IBM |  |  | 200 | mA |  | 2 |
| total power dissipation | Ptot |  |  | 250 | mW | Tamb ≤ 25 °C [1] | 2 |
| junction temperature | Tj |  |  | 150 | °C |  | 2 |
| ambient temperature | Tamb | -65 |  | 150 | °C |  | 2 |
| storage temperature | Tstg | -65 |  | 150 | °C |  | 2 |
| thermal resistance from junction to ambient | Rth(j-a) |  |  | 500 | K/W | [1] device mounted on FR4 PCB, single-sided copper, tin-plated, standard footprint | 2 |
| collector-base cut-off current | ICBO |  |  | 15 | nA | VCB = 30 V; IE = 0 A; Tj = 25 °C | 3 |
| collector-base cut-off current | ICBO |  |  | 5 | µA | VCB = 30 V; IE = 0 A; Tj = 150 °C | 3 |
| emitter-base cut-off current | IEBO |  |  | 100 | nA | VEB = 5 V; IC = 0 A; Tj = 25 °C | 3 |
| DC current gain | hFE | 200 | 290 | 450 | - | VCE = 5 V; IC = 2 mA; Tj = 25 °C | 3 |
| collector-emitter saturation voltage | VCEsat |  | 90 | 250 | mV | IC = 10 mA; IB = 0.5 mA; Tj = 25 °C | 3 |
| collector-emitter saturation voltage | VCEsat |  | 200 | 600 | mV | IC = 100 mA; IB = 5 mA; Tj = 25 °C | 3 |
| base-emitter voltage | VBE | 580 | 660 | 700 | mV | VCE = 5 V; IC = 2 mA; Tj = 25 °C [2] | 3 |
| base-emitter voltage | VBE |  |  | 770 | mV | VCE = 5 V; IC = 10 mA; Tj = 25 °C [2] | 3 |
| transition frequency | fT | 100 |  |  | MHz | VCE = 5 V; IC = 10 mA; f = 100 MHz; Tj = 25 °C | 3 |
| noise figure | NF |  |  | 4 | dB | VCE = 5 V; IC = 200 µA; RS = 2 kΩ; B = 200 Hz; f = 10 Hz to 15.7 kHz; Tj = 25 °C | 3 |

## CAD (KiCad official)

- Symbol: `BC850B`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `bc850b-etched.step` / `bc850b-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `bc850b.step` / `bc850b.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Nexperia datasheet](https://assets.nexperia.com/documents/data-sheet/BC850B.pdf) (9 pp, sha256 `b98ca97d7116de48`, retrieved 2026-09-23, tier: manufacturer)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.2`, primary `claude-haiku-4-5-20251001` (text), consensus `claude-sonnet-4-6` (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/bc850b-datasheet.pdf)