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TIP122 NPN Darlington Transistor

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by adom

NPN Darlington power transistor, 100 V / 5 A, high current gain in TO-220.

transistordarlingtonnpnpowerto-220st
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3D Model

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Datasheet

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Contents

README

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TIP122

STMicroelectronics · Bipolar Transistor (BJT) · TO-220

The TIP122 is a NPN Darlington power transistor rated for 100 V and 5 A continuous collector current. Its Darlington pair gives high current gain, so a small base drive from an MCU or logic pin switches large loads. It comes in a TO-220 package with integrated base-emitter resistors, part of the TIP120-127 complementary series.

Pinout

Pin Name Type Function
1 B input Base of the Darlington pair. Drive with IB up to 120 mA (absolute max); VBE(on) ≈ 2.5 V at IC = 3 A. Internal 7 kΩ resistor R1 sits between B and E, and R2 = 70 Ω is in series with the output-transistor base.
2 C passive Collector of the Darlington pair; also electrically connected to the TAB (heatsink mounting tab) for thermal dissipation. Rated VCEO = 100 V, IC = 5 A DC / 8 A peak.
3 E passive Emitter of the Darlington pair. Typically returned to the load's low-side rail (ground) in switching applications.

Key specifications

Parameter Value
Type NPN Darlington power transistor
Collector-emitter voltage (VCEO) 100 V
Collector current (IC) 5 A continuous (8 A peak)
DC current gain (hFE) 1000 min at 3 A
Power dissipation 65 W
Operating temperature -65 C to 150 C

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-emitter voltage (IB = 0 A) VCEO 100 V 2
Collector-base voltage (IE = 0 A) VCBO 100 V 2
Collector-base voltage (IC = 0 A) VEBO 5 V 2
Collector current IC 5 A 2
Collector peak current ICM 8 A 2
Base current IB 0.12 A 2
Total power dissipation PTOT 65 W TC ≤ 25°C 2
Total power dissipation PTOT 2 W TA ≤ 25°C 2
Storage temperature range Tstg -65 150 °C 2
Maximum operating junction temperature TJ 150 °C 2
Thermal resistance, junction-to-case RthJC 1.92 °C/W 2
Thermal resistance, junction-to-ambient RthJA 62.5 °C/W 2
Collector cut-off current ICEO 0.5 mA IB = 0 A, VCE = 50 V for TIP122/127 3
Collector cut-off current ICBO 0.2 mA IB = 0 A, VCE = 100 V for TIP122/127 3
Emitter cut-off current IEBO 2 mA IC = 0 A, VEB = 5 V 3
Collector-emitter sustaining voltage VCEO(sus) 100 V IB = 0 A, IC = 30 mA for TIP122/127 3
Collector-emitter saturation voltage VCE(sat) 2 V IC = 3 A, IB = 12 mA 3
Collector-emitter saturation voltage VCE(sat) 4 V IC = 5 A, IB = 20 mA 3
Base-emitter on voltage VBE(on) 2.5 V IC = 3 A, VCE = 3 V 3
DC current gain hFE 1000 IC = 0.5 A, VCE = 3 V 3

CAD (KiCad official)

  • Symbol: tip122.kicad_sym
  • Footprint: tip122.kicad_mod
  • 3D model: TO-220 body from KiCad Package_TO_SOT_THT/TO-220-3_Vertical.
  • 3D model files: tip122-etched.step / tip122-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); tip122.step / tip122.glb are the bare package body.

Provenance

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

  • Datasheet: STMicroelectronics datasheet (13 pp, sha256 e726b0e3ab76c110, retrieved 2026-08-17, tier: manufacturer)
  • Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF