STMicroelectronics

ULN2802A

ULN2802A Description

The ULN2802A from STMicroelectronics is a high-voltage, high-current 8-channel NPN Darlington transistor array designed for interfacing between low-level logic circuits and high-power peripheral devices. Housed in an 18-pin DIP package, it integrates eight Darlington pairs with common emitters, each capable of handling 500mA collector current (Ic) and 50V collector-emitter breakdown voltage (Vce). With a minimum DC current gain (hFE) of 1000 @ 350mA, 2V, it ensures efficient signal amplification and switching performance. The device features a low Vce saturation voltage (1.6V @ 500µA, 350mA), reducing power dissipation and improving thermal efficiency.

ULN2802A Features

• 8 NPN Darlington Transistors: Integrated array simplifies multi-channel designs.
• High Current Handling: Supports 500mA per channel (350mA continuous) for driving relays, motors, and LEDs.
• Low Saturation Voltage: 1.6V max @ 350mA minimizes power loss.
• High Voltage Tolerance: 50V Vce rating for robust operation in industrial environments.
• High Current Gain (hFE): 1000 min ensures reliable low-input-current switching.
• Wide Compatibility: TTL, CMOS, and PMOS logic input compatible.
• Durable Packaging: Through-hole 18DIP for easy prototyping and production.
• Compliance: ROHS3, REACH Unaffected, ECCN EAR99, and MSL 1 (Unlimited) for global use.

ULN2802A Applications

• Industrial Control Systems: Driving solenoids, relays, and stepper motors.
• Automotive Electronics: Load switching in dashboard displays and actuators.
• Consumer Electronics: LED matrix drivers and printer head control.
• Embedded Systems: Interface expansion for microcontrollers (e.g., Arduino, Raspberry Pi).
• Power Management: Multi-channel power supply sequencing.

Conclusion of ULN2802A

The ULN2802A excels in high-current, multi-channel switching applications, offering low saturation loss, high gain, and robust voltage handling. Its Darlington configuration reduces external component count, while compliance with environmental standards ensures reliability. Ideal for industrial, automotive, and embedded systems, it bridges the gap between logic circuits and power-hungry loads with unmatched efficiency.