# KRA105S-RTK

**KEC Semicon** · Digital Transistors · SOT-23

KRA105S-RTK from KEC Semicon, 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 | COMMON (EMITTER) | passive | Common emitter terminal of the built-in-bias PNP transistor, marked COMMON(+) in the equivalent circuit, with no separate voltage or current limit given for this pin. |
| 2 | IN (BASE) | input | Base input through the internal input resistor R1 (2.2 kΩ for KRA105S), with a rated input voltage of -12 V to 5 V for this type. |
| 3 | OUT (COLLECTOR) | output | Collector output with a rated output voltage of -50 V and output current of -100 mA, with device power dissipation of 200 mW. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | KEC Semicon |
| 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 |
|---|---|---|---|---|---|---|---|
| Output Cut-off Current (KRA101S-106S, applies to KRA105S) | IO(OFF) |  |  | -500 | nA | VO=-50V, VI=0 | 2 |
| DC Current Gain (KRA105S) | GI | 80 | 200 |  |  | VO=-5V, IO=-10mA | 2 |
| Output Voltage (ON) (KRA101S-106S, applies to KRA105S) | VO(ON) |  | -0.1 | -0.3 | V | IO=-10mA, II=-0.5mA | 2 |
| Input Voltage (ON) (KRA105S) | VI(ON) |  | -0.8 | -1.1 | V | VO=-0.2V, IO=-5mA | 2 |
| Input Voltage (OFF) (KRA105S) | VI(OFF) | -0.5 | -0.65 |  | V | VO=-5V, IO=-0.1mA | 2 |
| Input Current (KRA105S) | II |  |  | -3.6 | mA | VI=-5V | 2 |
| Input Resistor R1 (KRA105S) | R1 | 1.54 | 2.2 | 2.86 | kΩ |  | 2 |
| Resistor Ratio R2/R1 (KRA105S) | R2/R1 | 17 | 21 | 26 |  |  | 2 |
| Output Voltage (absolute maximum, KRA101S-106S) | VO | -50 |  |  | V |  | 1 |
| Input Voltage (absolute maximum, KRA105S) | VI | -12 |  | 5 | V |  | 1 |
| Output Current (absolute maximum, KRA101S-106S) | IO | -100 |  |  | mA |  | 1 |
| Power Dissipation | PD |  |  | 200 | mW |  | 1 |
| Junction Temperature | Tj |  |  | 150 |  |  | 1 |
| Storage Temperature Range | Tstg | -55 |  | 150 |  |  | 1 |
| Bias Resistor R2 (KRA105S nominal) | R2 |  | 47 |  | kΩ |  | 1 |

## CAD (KiCad official)

- Symbol: `KRA105S-RTK`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `kra105s-rtk-etched.step` / `kra105s-rtk-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `kra105s-rtk.step` / `kra105s-rtk.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [KEC Semicon datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8586180915969576960) (6 pp, sha256 `db5b473a62ff76f3`, retrieved 2026-10-19, 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/kra105s-rtk-datasheet.pdf)