# MMBTA42-RTK

**KEC Semicon** · Bipolar (BJT) · SOT-23

MMBTA42-RTK from KEC Semicon, 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 | EMITTER | passive | Emitter of the NPN transistor; emitter-base voltage VEBO max 5.0 V and emitter current IE max -500 mA. |
| 2 | BASE | passive | Base of the NPN transistor; drive conditions in the datasheet use IB=2.0 mA for VCE(sat)/VBE(sat) at IC=20 mA. |
| 3 | COLLECTOR | passive | Collector of the NPN transistor; MMBTA42 VCBO/VCEO 300 V and collector current IC max 500 mA. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | KEC Semicon |
| 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 | V(BR)CBO | 300 |  |  | V | IC=100μA, IE=0 | 1 |
| Collector-Emitter Breakdown Voltage | V(BE)CEO | 300 |  |  | V | IC=1.0mA, IB=0 | 1 |
| DC Current Gain | hFE | 40 |  |  |  | IC=1.0mA, VCE=10V | 1 |
| Collector-Emitter Saturation Voltage | VCE(sat) |  |  | 0.5 | V | IC=20mA, IB=2.0mA | 1 |
| Base-Emitter Saturation Voltage | VBE(sat) |  |  | 0.9 | V | IC=20mA, IB=2.0mA | 1 |
| Transition Frequency | fT | 50 |  |  | MHz | VCE=20V, IC=10mA, f=100MHz | 1 |
| Collector Output Capacitance | Cob |  |  | 3 | pF | VCB=20V, IE=0, f=1MHz | 1 |
| Collector-Base Voltage | VCBO |  |  | 300 | V | Ta=25℃ | 1 |
| Collector-Emitter Voltage | VCEO |  |  | 300 | V | Ta=25℃ | 1 |
| Emitter-Base Voltage | VEBO |  |  | 5 | V | Ta=25℃ | 1 |
| Collector Current | IC |  |  | 500 | mA | Ta=25℃ | 1 |
| Emitter Current | IE | -500 |  |  | mA | Ta=25℃ | 1 |
| Collector Power Dissipation | PC |  |  | 350 | mW | Ta=25℃; package mounted on 99.5% alumina 10×8×0.6mm | 1 |
| Junction Temperature | Tj |  |  | 150 | ℃ | Ta=25℃ | 1 |
| Storage Temperature | Tstg | -55 |  | 150 | ℃ | Ta=25℃ | 1 |

## CAD (KiCad official)

- Symbol: `MMBTA42-RTK`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `mmbta42-rtk-etched.step` / `mmbta42-rtk-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `mmbta42-rtk.step` / `mmbta42-rtk.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [KEC Semicon datasheet](docs/mmbta42-rtk-datasheet.pdf) (2 pp, sha256 `ab70af63ca748e85`, retrieved 2026-10-27, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-sonnet-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/mmbta42-rtk-datasheet.pdf)