2N3771

2N3771 / 2N3772 Silicon Epitaxial-Base NPN Transistor Technical Summary

Overview

The 2N3771 and 2N3772 are high-power silicon epitaxial-base NPN transistors designed for demanding industrial and commercial applications requiring robust performance. Housed in the industry-standard JEDEC TO-3 metal package, these transistors offer excellent thermal characteristics and high current handling capabilities. The epitaxial-base construction ensures superior switching speeds and linearity compared to conventional power transistors.

These devices are particularly well-suited for applications requiring sustained high-power operation, with special attention given to thermal management through the TO-3 package's efficient heat dissipation properties. The 2N3771/2N3772 series represents a reliable solution for power amplification and switching applications across various industries.

Key Features

• High current capability with 30A continuous collector current rating
• Excellent power dissipation: 150W at 25°C case temperature
• High voltage operation: V_CEO of 60V (2N3771) and 80V (2N3772)
• Low collector-emitter saturation voltage for improved efficiency
• Epitaxial-base construction for enhanced performance
• JEDEC TO-3 metal package for optimal thermal management
• Designed for linear amplification and switching applications
• Robust construction suitable for industrial environments

Applications

The 2N3771/2N3772 transistors find use in a wide range of power electronics applications, including:

• Power Amplifiers: High-fidelity audio amplifiers, industrial control amplifiers
• Switching Regulators: DC-DC converters, voltage regulators
• Motor Control: Servo amplifiers, motor drivers
• Power Supplies: Linear and switching power supplies
• Industrial Equipment: Welding equipment, power inverters
• Automotive Systems: Ignition systems, power controllers
• General Purpose Switching: Relay drivers, solenoid controls

Electrical Characteristics

All specifications are given at T_C = 25°C unless otherwise noted.

Absolute Maximum Ratings

• Collector-Emitter Voltage (V_CEO): 60V (2N3771), 80V (2N3772)
• Collector-Base Voltage (V_CBO): 100V (2N3771), 120V (2N3772)
• Emitter-Base Voltage (V_EBO): 7V
• Continuous Collector Current (I_C): 30A
• Total Power Dissipation (P_D): 150W at T_C ≤ 25°C
• Operating Junction Temperature Range (T_J): -65°C to +200°C
• Storage Temperature Range: -65°C to +200°C

Thermal Characteristics

• Thermal Resistance, Junction to Case (R_θJC): 0.7°C/W
• Thermal Resistance, Junction to Ambient (R_θJA): 35°C/W

DC Current Gain Characteristics

• DC Current Gain (h_FE): 15-60 @ I_C = 4A, V_CE = 4V
• Collector-Emitter Saturation Voltage (V_CE(sat)): 1.5V max @ I_C = 8A, I_B = 0.8A
• Base-Emitter Saturation Voltage (V_BE(sat)): 2.0V max @ I_C = 8A, I_B = 0.8A

Switching Characteristics

• Turn-On Time (t_on): 0.5μs typical
• Turn-Off Time (t_off): 2.5μs typical
• Fall Time (t_f): 1.0μs typical

Package Information

The 2N3771/2N3772 transistors are packaged in the JEDEC TO-3 metal can package, which provides excellent thermal performance and mechanical durability. The package details include:

• Package Type: TO-3 (JEDEC)
• Material: Metal can with epoxy seal
• Terminals:
  • Base (B)
  • Collector (C) - connected to case
  • Emitter (E)
• Mounting: Requires insulating hardware when collector/case cannot be grounded
• Weight: Approximately 11 grams
• Dimensions:
  • Diameter: 16.5mm
  • Height: 19.0mm (excluding terminals)
  • Terminal length: 19.0mm

Reliability and Qualification

The 2N3771/2N3772 transistors are designed to meet stringent reliability requirements:

• Manufactured using controlled silicon epitaxial process
• 100% electrical testing at elevated temperatures
• Meets or exceeds JEDEC standards for power transistors
• Qualified for industrial temperature range operation
• Hermetic metal package prevents moisture ingress

Handling and Installation Considerations

For optimal performance and reliability, observe the following guidelines:

• Use proper heatsinking to maintain junction temperature within limits
• Apply thermal compound between package and heatsink
• Use insulating hardware when collector cannot be grounded
• Avoid exceeding maximum ratings, especially during switching
• Observe proper ESD precautions during handling
• Ensure proper lead bending to avoid stress on glass seals

Alternative Components

For design flexibility, consider these alternative devices:

• 2N3773: Higher voltage version (100V V_CEO)
• 2N3055: Lower power alternative (15A, 60V)
• MJ15003: Complementary PNP version
• MJ15024: Higher performance NPN alternative

Conclusion

The 2N3771 and 2N3772 power transistors represent a robust solution for high-current, high-power applications requiring reliable performance. Their combination of high current capability, excellent thermal characteristics, and proven reliability make them suitable for demanding industrial and commercial applications. The TO-3 package ensures efficient heat dissipation, while the epitaxial-base construction provides superior electrical performance compared to conventional power transistors.

When properly heatsinked and operated within specified limits, these devices offer long service life and consistent performance in power amplification and switching circuits. Designers should pay particular attention to thermal management and voltage/current derating when operating at elevated temperatures.