# SS8550W

**TWGMC** · Bipolar (BJT) · SOT-323

SS8550W from TWGMC, in a SOT-323. 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 PNP transistor; the emitter-base breakdown voltage is limited to -5 V (VEBO maximum rating -5 V) and the base-emitter saturation voltage is -1.2 V at IC=-800mA, IB=-80mA. |
| 2 | EMITTER | passive | Emitter terminal of the PNP transistor; the emitter-base breakdown voltage V(BR)EBO is -5 V minimum at IE=-100µA, and VEBO is rated at -5 V. |
| 3 | COLLECTOR | passive | Collector terminal of the PNP transistor; rated for -1.5 A continuous collector current, VCEO -25 V, VCBO -40 V, and 0.2 W collector power dissipation. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | TWGMC |
| Package | SOT-323 |
| 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 | -40 |  |  | V | IC=-100µA, IE=0 | 1 |
| Collector-emitter breakdown voltage | V(BR)CEO | -25 |  |  | V | IC=-0.1mA, IB=0 | 1 |
| Emitter-base breakdown voltage | V(BR)EBO | -5 |  |  | V | IE=-100µA, IC=0 | 1 |
| Collector cut-off current | ICBO |  |  | -0.1 | µA | VCB=-40V, IE=0 | 1 |
| Emitter cut-off current | IEBO |  |  | -0.1 | µA | VEB=-5V, IC=0 | 1 |
| DC current gain | hFE(1) | 120 |  | 400 |  | VCE=-1V, IC=-100mA | 1 |
| DC current gain | hFE(2) | 40 |  |  |  | VCE=-1V, IC=-800mA | 1 |
| Collector-emitter saturation voltage | VCE(sat) |  |  | -0.5 | V | IC=-800mA, IB=-80mA | 1 |
| Base-emitter saturation voltage | VBE(sat) |  |  | -1.2 | V | IC=-800mA, IB=-80mA | 1 |
| Base-emitter on voltage | VBE(on) |  |  | -1 | V | IC=-1V, VCE=-10mA | 1 |
| Base-emitter positive favor voltage | VBEF |  |  | -1.55 | V | IB=-1A | 1 |
| Transition frequency | fT | 100 |  |  | MHz | VCE= -10V, IC= -50mA, f=30MHz | 1 |
| Output capacitance | Cob |  |  | 20 | pF | VCB=-10V, IE=0, f=1MHz | 1 |
| Collector-emitter voltage | VCEO | -25 |  |  | V |  | 1 |
| Collector-base voltage | VCBO | -40 |  |  | V |  | 1 |
| Emitter-base voltage | VEBO | -5 |  |  | V |  | 1 |
| Collector current, continuous | IC | -1.5 |  |  | A |  | 1 |
| Collector power dissipation | PC |  |  | 0.2 | W |  | 1 |
| Junction temperature | Tj |  |  | 150 | ℃ |  | 1 |
| Storage temperature | Tstg | -55 |  | 150 | ℃ |  | 1 |

## CAD (KiCad official)

- Symbol: `SS8550W`
- Footprint: `Package_TO_SOT_SMD:SOT-323_SC-70`
- 3D model: SOT-323 (KiCad packages3D, STEP)
- 3D model files: `ss8550w-etched.step` / `ss8550w-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `ss8550w.step` / `ss8550w.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [TWGMC datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8590891622085713920) (3 pp, sha256 `fd00ca2500b299d0`, retrieved 2026-10-09, 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/ss8550w-datasheet.pdf)