component
TIP121
Public Made by Adomby adom
STMicroelectronics Darlington Transistors, TO-220-3. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
3D Model
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Symbol & Footprint
Schematic Symbol
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PCB Footprint
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Datasheet
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README
markdownTIP121
STMicroelectronics · Darlington Transistors · TO-220-3
TIP121 from STMicroelectronics, in a TO-220-3. 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 | B | input | Base terminal of the monolithic NPN Darlington, with internal R1 = 7 kΩ and R2 = 70 Ω, and base current limited to 0.12 A (absolute maximum). |
| 2 | C | passive | Collector terminal, electrically connected to the metal tab; rated 80 V VCEO and 80 V VCBO for TIP121, 5 A continuous collector current and 8 A peak (ICM). |
| 3 | E | passive | Emitter terminal of the NPN Darlington; the emitter-base voltage is rated at 5 V maximum (VEBO). |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | STMicroelectronics |
| Package | TO-220-3 |
| Category | Transistors/Thyristors |
| Pins | 3 |
CAD (KiCad official)
- Symbol:
TIP121 - Footprint:
Package_TO_SOT_THT:TO-220-3_Vertical - 3D model: TO-220-3 (KiCad packages3D, STEP)
- 3D model files:
tip121-etched.step/tip121-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);tip121.step/tip121.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: STMicroelectronics datasheet (13 pp, sha256
e726b0e3ab76c110, retrieved 2026-10-08, tier: lcsc) - Extractor: parts-factory
2.0.0/extract_pins 0.3, primaryclaude-haiku-5-5(text), consensusclaude-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).