STMicroelectronics ULN2004A 7-Channel NPN Darlington Transistor Array, 500 mA 50 V 16-Pin PDIP

The STMicroelectronics ULN2004A is a high-performance seven-channel NPN Darlington transistor array designed to drive high-voltage and high-current loads from logic-level input signals. With a maximum continuous collector current of 500 mA per channel and a collector-emitter voltage rating of up to 50 V, the ULN2004A enables reliable switching of relays, solenoids, and lamps in a broad array of industrial and automation equipment.

This device integrates seven independent open-collector Darlington pairs, arranged in a 16-pin through-hole PDIP package that facilitates straightforward circuit board layout and compact design. Its high current gain (minimum hFE of 1000) supports low-power TTL and CMOS input compatibility, allowing seamless interfacing with standard logic devices for signal amplification, level shifting, and driving moderate power actuators without external transistors.

The ULN2004A is engineered with built-in suppression diodes, safeguarding output stages and external inductive loads from voltage transients that can occur during switching events. These integrated protection features enhance circuit robustness in demanding applications, reducing the need for additional external components and saving valuable PCB space.

Designed to operate within a temperature range of -20°C to 85°C, the package offers reliability across varied industrial and automotive environments. It features a standard pinout for easy drop-in replacement with compatible arrays. Each output channel can handle up to 500 mA, and all drive stages provide a guaranteed collector-emitter saturation voltage for predictable switching performance. The compact 20 mm × 5.1 mm form factor allows implementation in dense control panels, PLCs, and instrumentation boards.

Common use cases include relay and lamp matrix driving, stepper motor interfaces, digital valve and solenoid actuation, and industrial process control applications, where reliable, repetitive switching of moderate-power loads is essential for safe operation. Compatible with a range of input voltage levels, it preserves logic signal integrity and facilitates robust signal translation between control logic and output power stages.

Its reliability, integral protection features, and ease of assembly make the STMicroelectronics ULN2004A an essential choice for engineers designing industrial automation, test equipment, building management systems, and automotive driver circuits. Explore more Darlington Transistor and power driver solutions in the EnvMart Electromechanical and Semiconductor categories.