# KST8550D

**KEXIN** · Bipolar (BJT) · SOT-23

KST8550D from KEXIN, 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 | Base | input | Base terminal of the PNP transistor; the datasheet rates the emitter-base voltage VEBO at -5 V and the device for collector current IC = -1.5 A. |
| 2 | Emitter | passive | Emitter terminal of the PNP transistor; the emitter-base breakdown voltage VEBO is rated at -5 V maximum. |
| 3 | Collector | passive | Collector terminal of the PNP transistor; the datasheet rates the collector-base voltage VCBO at -40 V and the collector-emitter voltage VCEO at -25 V. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | KEXIN |
| 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 |  |  | -40 | V |  | 1 |
| Collector-emitter voltage | VCEO |  |  | -25 | V |  | 1 |
| Emitter-base voltage | VEBO |  |  | -5 | V |  | 1 |
| Collector current | IC |  |  | -1.5 | A |  | 1 |
| Collector power dissipation | PC |  |  | 0.3 | W |  | 1 |
| Junction temperature | Tj |  |  | 150 | °C |  | 1 |
| Storage temperature | Tstg | -55 |  | 150 | °C |  | 1 |
| Collector-base breakdown voltage | VCBO | -40 |  |  | V | IC=-100 A, IE=0 | 1 |
| Collector-emitter breakdown voltage | VCEO | -25 |  |  | V | IC=-1mA, IB=0 | 1 |
| Emitter-base breakdown voltage | VEBO | -5 |  |  | V | IE=-100 A, IC=0 | 1 |
| Collector cut-off current | ICBO |  |  | -1 | A | VCB=-40V, IE=0 | 1 |
| Emitter cut-off current | IEBO |  |  | -1 | A | VEB=-5V, IC=0 | 1 |
| DC current gain | hFE | 120 |  | 400 |  | VCE=-1V, IC=-100mA | 1 |
| DC current gain | hFE | 40 |  |  |  | VCE=-1V, IC=-800mA | 1 |
| Collector-emitter saturation voltage | VCE(sat) |  |  | -0.5 | V | IC=-800mA, IB=-80mA | 1 |
| Base-emitter on voltage | VBE(on) |  |  | -1 | V | VCE=-1V, IC=-10mA | 1 |
| Output capacitance | Cob |  |  | 20 | pF | VCB=-10V, IE=0, f=1MHz | 1 |
| Transition frequency | fT | 100 |  |  | MHz | VCE=-10V, IC=-50mA, f=30MHz | 1 |

## CAD (KiCad official)

- Symbol: `KST8550D`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `kst8550d-etched.step` / `kst8550d-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `kst8550d.step` / `kst8550d.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [KEXIN datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8588903910828888064) (2 pp, sha256 `3c116c6d7eb4e315`, retrieved 2026-10-18, 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/kst8550d-datasheet.pdf)