ULN2003 Darlington Transistor Arrays Datasheet, Features, Pinout, and Applications

The ULN2003 is a high-voltage, high-current Darlington transistor array IC designed to drive inductive loads such as motors, relays, and solenoids. Manufactured by several semiconductor companies, the ULN2003 is a popular choice in automotive, industrial, and consumer applications. Its robust design, high load-driving capacity, and ease of use make it an indispensable component for interfacing low-power logic circuits with high-power loads.

Overview of ULN2003

The ULN2003 series consists of high-voltage, high-current Darlington transistor arrays. Each device includes seven NPN Darlington pairs, designed with high-voltage outputs and common-cathode clamp diodes to facilitate the switching of inductive loads.

Each Darlington pair supports a collector current of up to 500 mA, and multiple pairs can be connected in parallel to achieve higher current handling capabilities. These devices are ideal for a wide range of applications, including relay driving, hammer driving, lamp driving, LED and gas discharge display driving, line driving, and logic buffering.

ULN2003 Features

• Supports a collector current of up to 500 mA per output
• High-voltage output capability up to 50V
• Integrated output clamp diodes for enhanced performance
• Compatible with multiple logic input standards
• Optimized for relay-driving applications

Absolute Maximum Ratings

ULN2003 Pinout

Pin Configuration and Functions

Simplified Block Diagram

Functional Block Diagrams

ULN2003 Application

Relay Drivers

The ULN2003 is widely used in relay driving circuits, where it serves as an interface between low-power control signals and high-power relays. It enables microcontrollers or logic-level devices to control high-current relays safely and efficiently. This application is common in automation systems, home appliances, and industrial machinery where reliable switching of circuits is required.

Stepper and DC Brushed Motor Drivers

When driving stepper motors or DC brushed motors, the ULN2003 simplifies circuit design by providing high-current outputs that can handle the inductive loads typical of these motors. It ensures precise control over motor operation, making it suitable for applications such as robotic arms, CNC machines, 3D printers, and other motion control systems.

Lamp Drivers

The ULN2003 is often employed in lamp-driving circuits for its ability to handle higher currents and its built-in protection features. It is used to drive incandescent bulbs, halogen lamps, and other lighting systems, ensuring stable operation. This makes it a key component in automotive lighting, decorative light displays, and warning signals.

Display Drivers (LED and Gas Discharge)

For LED and gas discharge displays, the ULN2003 acts as a driver that translates low-power control signals into the higher power levels required by these displays. It ensures uniform brightness and reliable operation, commonly seen in digital billboards, industrial status panels, and seven-segment displays used in instrumentation.

Line Drivers

In communication and control systems, the ULN2003 functions as a line driver to boost signals for transmission over longer distances or through noise-prone environments. Its robust output capabilities make it ideal for industrial automation networks, remote sensing applications, and building control systems.

Logic Buffers

As a logic buffer, the ULN2003 isolates and strengthens signals from low-power logic circuits, enabling them to drive higher current loads. This role is critical in digital systems where the integration of high-power devices with low-power logic is necessary, such as in control panels, signal processing circuits, and embedded systems.

Typical Application Circuit

ULN2003A Device as Inductive Load Driver

ULN2003 Package

The ULN2003 is available in DIP-16 and SOP-16 packages, designed for through-hole and surface-mount PCB layouts. These compact packages ensure easy integration while providing efficient thermal management, suitable for high-density designs in consumer, automotive, and industrial systems.

ULN2003 Manufacturer

The ULN2003 Darlington Transistor Array IC is manufactured by several semiconductor companies, including Texas Instruments, STMicroelectronics, and ON Semiconductor, ensuring wide availability and compatibility with a variety of designs.

ULN2003 Datasheet

The ULN2003 datasheet provides comprehensive details on electrical characteristics, pin configurations, and design guidelines. Engineers can refer to the datasheet to optimize the integration of the ULN2003 into their systems for reliable and efficient operation.

ULN2003 vs. Other Darlington Arrays

• ULN2003 vs. ULN2803: The ULN2803 provides 8 channels instead of 7, making it suitable for applications requiring more outputs. However, the ULN2003 is a better choice for compact designs with fewer channels.
• ULN2003 vs. L298N: While the L298N is a dual H-bridge motor driver, the ULN2003 is a Darlington array optimized for driving multiple individual loads, such as relays and solenoids.
• ULN2003 vs. TPIC6B595: The TPIC6B595 offers shift register functionality, combining logic control and current driving. The ULN2003, however, provides simpler direct interfacing and higher current handling per channel.

Popular ULN2003 ICs

Conclusion

The ULN2003 Darlington Transistor Array is a versatile and reliable solution for driving high-current loads in embedded systems. With its high voltage and current handling capacity, integrated protection features, and compatibility with TTL and CMOS logic, the ULN2003 is ideal for motor control, relay driving, and signal amplification applications. Its compact packaging and robust design ensure reliable performance in demanding environments, making it an indispensable component for modern electronics.

Read More

• LNK305 PMIC Datasheet, Features, Pinout, and Applications
• ST1S10 Switching Voltage Regulators Datasheet, Features, Pinout, and Applications
• MAX6033 Power Management ICs Datasheet, Pinout, Features, and Applications