# TIP137

**STMicroelectronics** · Darlington Transistors · TO-220

TIP137 from STMicroelectronics, in a TO-220. 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 control terminal of Darlington transistor with maximum base current rating of 0.3 A and maximum emitter-base voltage of 5 V. |
| 2 | Collector | passive | Collector terminal of Darlington transistor with maximum continuous collector current of 8 A (peak 12 A) and maximum collector-emitter voltage of 100 V, connected to metal tab for thermal dissipation. |
| 3 | Emitter | passive | Emitter terminal forming the main current return path with maximum emitter cut-off current of 5 mA when collector current is zero. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | STMicroelectronics |
| Package | TO-220 |
| Category | Transistors/Thyristors |
| Pins | 3 |

## CAD (KiCad official)

- Symbol: `TIP137`
- Footprint: `Package_TO_SOT_THT:TO-220-3_Vertical`
- 3D model: TO-220 (KiCad packages3D, STEP)
- 3D model files: `tip137-etched.step` / `tip137-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `tip137.step` / `tip137.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [STMicroelectronics datasheet](https://www.st.com/resource/en/datasheet/tip137.pdf) (4 pp, sha256 `b2a88a31161bd8e4`, retrieved 2026-10-06, tier: manufacturer)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-4-5-20251001` (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/tip137-datasheet.pdf)