What are the Darlington tube packages?

Darlington Transistors come in various packaging forms to accommodate different power levels, application scenarios, and design requirements. The packaging system of Darlington transistors is systematically analyzed from four dimensions: packaging type, technical characteristics, application scenarios, and selection suggestions.
1、 The main packaging types of Darlington transistors
1. TO-220（Transistor Outline-220）
Structural features: Three pin direct insertion package, metal heat sink connected to collector, size approximately 10.4mm × 9.8mm.
Technical parameters:
Maximum power dissipation (PD): 65W (requires heat sink)
Thermal resistance (R θ ja): 60 ℃/W (without heat sink), 1.5 ℃/W (with heat sink)
Typical applications: motor drive, power switch, LED lighting.
Representative models: TIP120/TIP125 from ON Semiconductor, YJD120 from Yangjie Technology.
2. TO-3（Transistor Outline-3）
Structural features: Metal shell packaging, pins lead out from the bottom, with dimensions of approximately 23.4mm × 15.2mm.
Technical parameters:
Maximum power dissipation (PD): 90W
Thermal resistance (R θ ja): 1 ℃/W
Typical applications: industrial frequency converters, audio power amplifiers, high-power regulated power supplies.
Representative models: MJ1000 from IXYS, L6203 from STMicroelectronics.
3. SOT-223（Small Outline Transistor-223）
Structural features: Surface mount packaging, four pins (including heat sink), size approximately 6.5mm × 3.5mm.
Technical parameters:
Maximum power dissipation (PD): 2W
Thermal resistance (R θ ja): 40 ℃/W
Typical applications: portable device power management, low-power motor drives, battery powered systems.
Representative models: ROHM's BD681, Dior's ZXTD2005E.
4. SOT-89（Small Outline Transistor-89）
Structural features: Surface mount packaging, three pins (including heat sink), size approximately 4.5mm × 2.5mm.
Technical parameters:
Maximum power dissipation (PD): 1.2W
Thermal resistance (R θ ja): 50 ℃/W
Typical applications: sensor interface, low-noise amplifier, miniaturized motor control.
Representative models: Panasonic's 2SC5200, ROHM's BD679.
5. TO-92（Transistor Outline-92）
Structural features: Three pin plastic packaging, with dimensions of approximately 4.3mm × 2.5mm.
Technical parameters:
Maximum power dissipation (PD): 0.625W
Thermal resistance (R θ ja): 200 ℃/W
Typical applications: low-power signal amplification, switch circuits, educational experiments.
Representative models: MPSA14, 2N3904 (some models have Darlington structure).
6. TO-247（Transistor Outline-247）
Structural features: High power direct insertion package, metal heat sink connected to collector, size approximately 15.6mm × 12.7mm.
Technical parameters:
Maximum power dissipation (PD): 150W
Thermal resistance (R θ ja): 0.5 ℃/W (with heat sink)
Typical applications: electric vehicle inverters, high-power laser drives, industrial welding equipment.
Representative models: Infineon's IKW40N120H3 (IGBT+Darlington module), IXYS' IXTK90N20L2.
2、 Comparison of technical characteristics of packaging types
3、 Key considerations for packaging selection
Power level and heat dissipation requirements
High power applications (>50W): Priority should be given to TO-247 or TO-3, equipped with forced air cooling/water cooling.
Medium power application (10-50W): Choose TO-220 with heat sink.
Low power applications (<10W): Choose SOT-223 or SOT-89 and use PCB copper foil for heat dissipation.
Space limitations and layout requirements
Dense design: Choose SOT-223/SOT-89 to reduce PCB footprint.
Plug in requirements: Choose TO-220/TO-3 for easy maintenance and replacement.
Cost sensitivity
Low cost scenario: Choose TO-92 or SOT-23, but sacrifice heat dissipation performance.
High performance requirements: Choose TO-247 or metal encapsulated TO-3 to ensure reliability.
4、 The development trend of packaging technology
Miniaturization and integration
Trend: The packaging size has evolved from TO-220 to SOT-223 and DFN (Dual Flat No led), with a size reduction of over 50%.
Case: ROHM's BD681 (SOT-223) has a volume only one-third that of TO-220.
High power density
Technology: Adopting silver sintering packaging and copper clip connection to improve thermal conductivity efficiency.
Case: Infineon's EKZ series has a power density of 200W/cm ³.
Intelligent packaging
Innovation: Integrating temperature sensors and overcurrent protection circuits to achieve intelligent power management.
Case: STripFET series from STMicroelectronics, with built-in NTC thermistor.
5、 Selection Decision Framework
Do you need vehicle level certification?
Yes → Choose TO-220 or TO-247, such as ON Semiconductor's TIP120 (AEC-Q101 certified).
No → Continue.
Is the load current greater than 10A?
Yes → Choose TO-247 or TO-3, such as IXTK90N20L2 (IC=90A) from IXYS.
No → Continue.
Do we need surface mount?
Yes → Select SOT-223 or SOT-89, such as ROHM's BD681.
No → Select TO-220 or TO-3.
Does it involve high-frequency switches?
Yes → Choose a low inductance package, such as SOT-223 (pin inductance<2nH).
No → Select traditional direct insertion packaging.
Based on the above analysis, a systematic selection of Darlington transistor packaging can be made to balance power, heat dissipation, space, and cost requirements. In practical applications, it is recommended to conduct thermal simulation (such as FloTHERM) and reliability testing based on specific scenarios to ensure accurate packaging selection.