# MSD42WT1G

**onsemi** · Bipolar (BJT) · SC-70

MSD42WT1G from onsemi, in a SC-70. 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 (Style 3, pin 1); the datasheet gives emitter-base breakdown voltage V(BR)EBO of 6.0 V minimum, with emitter-base cutoff current IEBO specified at VEB = 6.0 V. |
| 2 | EMITTER | passive | Emitter terminal of the NPN transistor (Style 3, pin 2); the device-level emitter-base voltage rating V(BR)EBO is 6.0 V and the continuous collector current rating IC is 150 mA. |
| 3 | COLLECTOR | passive | Collector terminal of the NPN transistor (Style 3, pin 3); the device-level collector-emitter voltage rating V(BR)CEO is 300 V and the collector-base voltage rating V(BR)CBO is 300 V. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | onsemi |
| Package | SC-70 |
| 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-Emitter Breakdown Voltage | V(BR)CEO | 300 |  |  | V | IC = 1.0 mA, IB = 0 | 1 |
| Collector-Base Breakdown Voltage | V(BR)CBO | 300 |  |  | V | IC = 100 A, IE = 0 | 1 |
| Emitter-Base Breakdown Voltage | V(BR)EBO | 6 |  |  | V | IE = 100 A, IE = 0 | 1 |
| Collector-Base Cutoff Current | ICBO |  |  | 0.1 | A | VCB = 200 V, IE = 0 | 1 |
| Emitter-Base Cutoff Current | IEBO |  |  | 0.1 | A | VEB = 6.0 V, IB = 0 | 1 |
| DC Current Gain | hFE1 | 25 |  |  |  | VCE = 10 V, IC = 1.0 mA | 1 |
| DC Current Gain | hFE2 | 40 |  |  |  | VCE = 10 V, IC = 30 mA | 1 |
| Collector-Emitter Saturation Voltage | VCE(sat) |  |  | 0.5 | V | IC = 20 mA, IB = 2.0 mA (Note 2) | 1 |
| Collector-Emitter Voltage | V(BR)CEO |  |  | 300 | V |  | 1 |
| Collector-Base Voltage | V(BR)CBO |  |  | 300 | V |  | 1 |
| Emitter-Base Voltage | V(BR)EBO |  |  | 6 | V |  | 1 |
| Collector Current - Continuous | IC |  |  | 150 | mA |  | 1 |
| Power Dissipation | PD |  |  | 450 | mW | FR-4 @ 10 mm2, 1 oz. Copper traces (Note 1) | 1 |
| Junction and Storage Temperature Range | TJ, Tstg | -55 |  | 150 | °C |  | 1 |
| Thermal Resistance, Junction-to-Ambient | RJA |  |  | 274 | °C/W | Note 1 (FR-4 @ 10 mm2, 1 oz. Copper traces) | 1 |

## CAD (KiCad official)

- Symbol: `MSD42WT1G`
- Footprint: `Package_TO_SOT_SMD:SOT-323_SC-70`
- 3D model: SC-70 (KiCad packages3D, STEP)
- 3D model files: `msd42wt1g-etched.step` / `msd42wt1g-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `msd42wt1g.step` / `msd42wt1g.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [onsemi datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8588927429541318656) (5 pp, sha256 `4c025293f8de204f`, retrieved 2026-11-06, 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/msd42wt1g-datasheet.pdf)