# TBC857B

**TOSHIBA** · Bipolar Transistors - BJT · SOT-23

TBC857B from TOSHIBA, in a SOT-23. 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; the datasheet limits base current to -30 mA (absolute maximum rating). |
| 2 | Emitter | passive | Emitter terminal; the datasheet limits emitter-base voltage to -5 V (absolute maximum rating). |
| 3 | Collector | passive | Collector terminal; the datasheet limits DC collector current to -150 mA and pulsed collector current to -200 mA (absolute maximum ratings). |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | TOSHIBA |
| Package | SOT-23 |
| Category | Triode/MOS Tube/Transistor |
| Pins | 3 |

## CAD (KiCad official)

- Symbol: `TBC857B`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `tbc857b-etched.step` / `tbc857b-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `tbc857b.step` / `tbc857b.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [TOSHIBA datasheet](docs/tbc857b-datasheet.pdf) (5 pp, sha256 `21874f95ad086bc5`, retrieved 2026-10-28, tier: manufacturer)
- **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/tbc857b-datasheet.pdf)