# MPSA42U

**CBI** · Bipolar (BJT) · SOT-89

MPSA42U from CBI, in a SOT-89. 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; VEBO max is 5 V and the emitter-base breakdown voltage V(BR)EBO is min 5 V at IE=100µA. |
| 2 | C | passive | Collector of the NPN transistor; VCBO and VCEO are both 300 V, with continuous collector current IC of 0.3 A. |
| 3 | E | passive | Emitter of the NPN transistor; the emitter-base breakdown voltage V(BR)EBO is min 5 V at IE=100µA. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | CBI |
| Package | SOT-89 |
| 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(BR)CEO | 300 |  |  | V | IC= 1mA, IB=0 | 1 |
| Emitter-base breakdown voltage | V(BR)EBO | 5 |  |  | V | IE= 100μA, IC=0 | 1 |
| Collector cut-off current | ICBO |  |  | 0.25 | μA | VCB=200V, IE=0 | 1 |
| Emitter cut-off current | IEBO |  |  | 0.1 | μA | VEB= 5V, IC=0 | 1 |
| DC current gain | hFE(1) | 60 |  |  |  | VCE= 10V, IC= 1mA | 1 |
| DC current gain | hFE(2) | 100 |  | 200 |  | VCE= 10V, IC=10mA | 1 |
| Collector-emitter saturation voltage | VCE(sat) |  |  | 0.2 | V | IC=20mA, IB= 2mA | 1 |
| Base-emitter saturation voltage | VBE(sat) |  |  | 0.9 | V | IC= 20mA, IB=2mA | 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 |  |  | 0.3 | A |  | 1 |
| Collector power dissipation | PC |  |  | 0.35 | W |  | 1 |
| Junction temperature | TJ |  |  | 150 | ℃ |  | 1 |
| Storage temperature | Tstg | -55 |  | 150 | ℃ |  | 1 |
| Thermal resistance, junction to ambient | RӨJA |  | 357 |  | ℃/mW |  | 1 |

## CAD (KiCad official)

- Symbol: `MPSA42U`
- Footprint: `Package_TO_SOT_SMD:SOT-89-3`
- 3D model: SOT-89 (KiCad packages3D, STEP)
- 3D model files: `mpsa42u-etched.step` / `mpsa42u-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `mpsa42u.step` / `mpsa42u.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [CBI datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8603129095669116928) (3 pp, sha256 `4f5c9a2a1811b02f`, retrieved 2026-10-18, tier: lcsc)
- **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/mpsa42u-datasheet.pdf)