# BF420-TA

**Changjing** · Bipolar (BJT) · TO-92

BF420-TA 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 NPN transistor; the datasheet's maximum emitter-base voltage (VEBO) rating is 5 V. |
| 2 | COLLECTOR | passive | Collector terminal of the NPN transistor; maximum collector-base and collector-emitter voltages are 300 V for BF420 and 250 V for BF422, with 100 mA continuous collector current. |
| 3 | BASE | passive | Base terminal of the NPN transistor; DC current gain hFE is 50 at VCE=20 V, IC=25 mA. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Changjing |
| Package | TO-92 |
| Category | Transistors/Thyristors |
| Pins | 3 |

## CAD (KiCad official)

- Symbol: `BF420-TA`
- Footprint: `Package_TO_SOT_THT:TO-92_Inline`
- 3D model: TO-92 (KiCad packages3D, STEP)
- 3D model files: `bf420-ta-etched.step` / `bf420-ta-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `bf420-ta.step` / `bf420-ta.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/8603027271934488576) (5 pp, sha256 `e2e62393384852fe`, retrieved 2026-10-09, 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/bf420-ta-datasheet.pdf)