# MMBTA42-6AF

**FOSAN** · Bipolar (BJT) · SOT-23

MMBTA42-6AF from FOSAN, 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 | B | input | Base of the NPN transistor; emitter-base voltage limited to 5 V (VEBO) and IEBO max 100 nA at VEB=5V. |
| 2 | E | passive | Emitter of the NPN transistor; collector current rated 300 mA continuous and 500 mA peak. |
| 3 | C | passive | Collector of the NPN transistor; VCBO and VCEO are both rated 300 V with 350 mW power dissipation. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | FOSAN |
| 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 |  |  | 300 | V |  | 1 |
| Collector-Emitter Voltage | VCEO |  |  | 300 | V |  | 1 |
| Emitter-Base Voltage | VEBO |  |  | 5 | V |  | 1 |
| Collector Current | IC |  |  | 300 | mA |  | 1 |
| Collector Peak Current | ICM |  |  | 500 | mA |  | 1 |
| Power dissipation | PC |  |  | 350 | mW | Ta=25℃ | 1 |
| Junction and Storage Temperature | TJ,Tstg | -55 |  | 150 | ℃ |  | 1 |
| Thermal Resistance Junction-Ambient | RΘJA |  |  | 357 | ℃/W |  | 1 |
| Collector-Base Breakdown Voltage | BVCBO | 300 |  |  | V | IC=100uA, IE=0 | 2 |
| Collector-Emitter Breakdown Voltage | BVCEO | 300 |  |  | V | IC=1mA, IB=0 | 2 |
| Emitter-Base Breakdown Voltage | BVEBO | 5 |  |  | V | IE=10uA, IC=0 | 2 |
| Collector-Base Leakage Current | ICBO |  |  | 100 | nA | VCB=300V, IE=0 | 2 |
| Collector-Emitter Leakage Current | ICEO |  |  | 100 | nA | VCE=200V, IB=0 | 2 |
| Emitter-Base Leakage Current | IEBO |  |  | 100 | nA | VEB=5V, IC=0 | 2 |
| DC Current Gain | HFE(1) | 60 |  |  |  | VCE=10V, IC=1mA | 2 |
| DC Current Gain | HFE(2) | 100 |  | 200 |  | VCE=10V, IC=10mA | 2 |
| Collector-Emitter Saturation Voltage | VCE(sat) |  |  | 0.2 | V | IC=20mA, IB=2mA | 2 |
| Base-Emitter Saturation Voltage | VBE(sat) |  |  | 0.9 | V | IC=20mA, IB=2mA | 2 |
| Transition Frequency | fT | 50 |  |  | MHZ | VCE=20V, IC=10mA | 2 |

## CAD (KiCad official)

- Symbol: `MMBTA42-6AF`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `mmbta42-6af-etched.step` / `mmbta42-6af-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `mmbta42-6af.step` / `mmbta42-6af.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [FOSAN datasheet](docs/mmbta42-6af-datasheet.pdf) (4 pp, sha256 `cef3e6d3eefaf027`, retrieved 2026-10-21, tier: lcsc)
- **Datasheet language:** Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-sonnet-5-5` (text+vision), consensus `claude-opus-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/mmbta42-6af-datasheet.pdf)