ULN2002A

Overview

The ULN2002A is a high-voltage, high-current seven-channel Darlington array manufactured by STMicroelectronics. It contains seven open-collector Darlington pairs with common emitters, each rated for a continuous collector current of 500 mA and capable of withstanding peak currents up to 600 mA. The device features an output voltage rating of 50 V and includes integrated suppression diodes connected to the common emitter line for driving inductive loads. Designed for compatibility with PMOS logic families operating between 14 V and 25 V, it interfaces directly with standard logic inputs. The component is available in 16-pin DIP and SO packages.

Feature Summary

• Seven independent Darlington driver channels per package
• Integrated suppression diodes for inductive load protection
• Input pins positioned opposite output pins to simplify PCB layout
• Outputs can be paralleled to increase total current handling capability

Applications

• Driving solenoids and relays
• Controlling DC motors
• Powering LED displays and filament lamps
• Operating thermal printheads
• High-power buffering applications

Procurement Notes

Verify the specific ordering suffix to confirm the package type, as the ULN2002A designation may correspond to different physical forms such as the 16-pin DIP or SO-16 variants. Ensure the selected version matches the required thermal resistance characteristics, particularly if utilizing the copper leadframe construction found in the 'A' series DIP packages. Confirm logic family compatibility with the 14–25 V PMOS input requirements before finalizing procurement.

Selection Notes

Select the ULN2002A specifically when the control logic operates within the 14 V to 25 V range, typically associated with PMOS families. Choose this variant over the ULN2003 if the system does not require 5 V TTL/CMOS compatibility. Consider the SO-16 package (ULN2002D1) if surface mount technology is preferred, noting that the pinout remains consistent with the through-hole version for design reuse.

Part Context

The ULN2002A belongs to the ULN200x/ULN200xA family of seven-channel Darlington arrays from STMicroelectronics. This family shares identical internal circuitry and electrical ratings but differs primarily in input resistor values to optimize interface compatibility with various logic families. While the ULN2003 targets 5 V systems, the ULN2002A is engineered for higher voltage PMOS applications, providing a versatile solution for mixed-voltage digital-to-analog interfacing tasks.

Replacement Considerations

Direct functional substitutes include the ULN2001A for general-purpose logic interfacing and the ULN2003A for 5 V TTL/CMOS systems. Cross-model replacement requires verifying that the target logic family voltage levels align with the ULN2002A's 14–25 V PMOS input specifications. Other manufacturers' equivalents must be checked for matching 500 mA channel current ratings and 50 V output voltage capabilities.