STMicroelectronics

ULN2066B

ULN2066B Description

The ULN2066B from STMicroelectronics is a high-voltage, high-current quad NPN Darlington transistor array designed for demanding switching applications. Housed in a 16-pin DIP package, it integrates four Darlington pairs capable of handling 1.75A collector current (Ic) per channel with a 50V collector-emitter breakdown voltage (Vce). This obsolete but robust device features a low Vce saturation voltage of 1.4V @ 2mA, 1.25A, ensuring efficient power dissipation and reduced heat generation. With a 1W maximum power rating, it is suitable for driving inductive loads such as relays, solenoids, and stepper motors. The device is ROHS3 compliant and REACH unaffected, meeting modern environmental standards.

ULN2066B Features

• Quad NPN Darlington Configuration: Four independent Darlington pairs for multi-channel switching.
• High Current Handling: Supports up to 1.75A per channel with a 50V Vce rating.
• Low Saturation Voltage: 1.4V @ 2mA, 1.25A minimizes power loss.
• Through-Hole Mounting: 16-pin DIP package for easy PCB integration.
• Robust Power Dissipation: 1W max power ensures reliability in high-load conditions.
• Environmental Compliance: ROHS3 and REACH unaffected, suitable for eco-conscious designs.
• Wide Operating Range: Ideal for industrial and automotive environments.

ULN2066B Applications

The ULN2066B excels in high-current switching systems, including:

• Relay and Solenoid Drivers: Provides stable, high-current switching for industrial control systems.
• Stepper Motor Controllers: Efficiently drives unipolar stepper motors in automation equipment.
• LED Display Drivers: Supports high-power LED matrices in signage and lighting.
• Automotive Load Switching: Used in automotive ECU designs for actuator control.
• Logic Interface Circuits: Bridges low-power logic (TTL, CMOS) to high-power loads.

Conclusion of ULN2066B

The ULN2066B is a versatile, high-performance Darlington array tailored for high-current inductive load switching. Its low saturation voltage, high current capacity, and robust packaging make it ideal for industrial, automotive, and consumer electronics. While marked as obsolete, its reliability and compliance with modern standards ensure continued suitability for legacy and maintenance designs. Engineers seeking a proven solution for multi-channel power switching will find the ULN2066B a dependable choice.