# KMBTA42

**KEXIN** · Bipolar (BJT) · SOT-23

KMBTA42 from KEXIN, 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 | input | Base terminal of the NPN transistor; the emitter-base breakdown voltage VEBO is rated at 5 V maximum. |
| 2 | Emitter | passive | Emitter terminal of the NPN transistor; the datasheet specifies emitter-base cut-off current IEBO of 0.1 µA at VEB = 5 V. |
| 3 | Collector | passive | Collector terminal of the NPN transistor; rated VCEO 300 V, VCBO 300 V, continuous collector current IC 500 mA, and collector power dissipation PC 350 mW at Ta = 25 ℃. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | KEXIN |
| 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 breakdown voltage | VCBO | 300 |  |  | V | Ic= 100 μA, IE= 0 | 1 |
| Collector-emitter breakdown voltage | VCEO | 300 |  |  | V | Ic= 1 mA, IB= 0 | 1 |
| Emitter-base breakdown voltage | VEBO | 5 |  |  | V | IE= 100 uA, IC= 0 | 1 |
| Collector-base cut-off current | ICBO |  |  | 0.1 | uA | VCB= 200 V, IE= 0 | 1 |
| Emitter cut-off current | IEBO |  |  | 0.1 | uA | VEB= 5V, IC=0 | 1 |
| Collector-emitter saturation voltage | VCE(sat) |  |  | 0.2 | V | IC= 20 mA, IB= 2mA | 1 |
| Base-emitter saturation voltage | VBE(sat) |  |  | 0.9 | V | IC= 20mA, IB= 2mA | 1 |
| DC current gain | hfe(1) | 60 |  |  |  | VCE= 10V, IC= 1mA | 1 |
| DC current gain | hfe(2) | 100 |  |  |  | VCE= 10V, IC= 10mA | 1 |
| Transition frequency | fT | 50 |  |  | MHz | VCE= 20V, IC= 10mA, f=30MHz | 1 |
| Collector-base voltage | VCBO |  |  | 300 | V |  | 1 |
| Collector-emitter voltage | VCEO |  |  | 300 | V |  | 1 |
| Emitter-base voltage | VEBO |  |  | 5 | V |  | 1 |
| Collector current - continuous | IC |  |  | 500 | mA |  | 1 |
| Collector power dissipation | PC |  |  | 350 | mW |  | 1 |
| Thermal resistance junction to ambient | RθJA |  |  | 357 | ℃/W |  | 1 |
| Junction temperature | TJ |  |  | 150 | ℃ |  | 1 |
| Storage temperature range | Tstg | -55 |  | 150 | ℃ |  | 1 |

## CAD (KiCad official)

- Symbol: `KMBTA42`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `kmbta42-etched.step` / `kmbta42-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `kmbta42.step` / `kmbta42.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [KEXIN datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8588904711046619136) (2 pp, sha256 `f2761eac90179006`, retrieved 2026-10-17, 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/kmbta42-datasheet.pdf)