E-ULN2004A

Overview

The ULN2004A is a high-voltage, high-current Darlington transistor array manufactured by STMicroelectronics. It integrates seven NPN Darlington pairs with common emitters and integrated suppression diodes for inductive load switching. Each channel supports a continuous collector current of 500 mA and withstands peak currents up to 600 mA, with an output voltage rating of 50 V. The device features a 10.5 kΩ series base resistor per input, enabling direct interface with CMOS logic operating between 6 V and 15 V. Packaged in a 16-pin DIP or SOIC format, it includes a copper leadframe to minimize thermal resistance.

Feature Summary

• Integrates seven open-collector NPN Darlington pairs with common emitters
• Includes built-in suppression diodes for efficient inductive load driving
• Features 10.5 kΩ series base resistors for direct 6V-15V CMOS compatibility
• Utilizes a copper leadframe design to reduce thermal resistance

Applications

• Relay driver circuits
• Stepper and DC brushed motor drivers
• LED and gas discharge tube (GDT) display drivers
• Line drivers and high-power logic buffers

Procurement Notes

Verify the specific package variant (PDIP or SOIC) and manufacturer origin during sourcing. Confirm active status as availability may vary across distributors. Ensure the component matches the required thermal and electrical specifications for the target application environment.

Selection Notes

Select this component when interfacing with 6V to 15V CMOS logic families requiring high current switching capabilities. Consider the ULN2003A if TTL or 5V CMOS compatibility is needed instead. Evaluate thermal management requirements based on the number of parallel outputs used, as paralleling channels increases current capacity but also heat generation.

Part Context

The ULN2004A belongs to the ULx200xA family of high-voltage Darlington arrays. It is distinguished from the ULN2003A by its higher base resistance, making it suitable for higher voltage CMOS inputs. The device shares structural similarities with the ULN2001A and ULN2002A but offers specific input characteristics tailored for different logic voltage levels.

Replacement Considerations

Publicly confirmed substitutes include the ULN2004ADG4 (TI) and generic equivalents like A2004. Verify pinout compatibility and electrical ratings before substitution. Note that some legacy variants may be marked as last-time-buy items.