This standard device has proven ubiquity and versatility across a wide range of applications. This feature is due to its integration of eight Darlington transistors that are capable of sinking up to 500 mA and wide GPIO range capability.

The ULN2803C is comprised of eight high voltage, high current NPN Darlington transistor pairs. All units feature a common emitter and open collector outputs. To maximize their effectiveness, these units contain suppression diodes for inductive loads. The ULN2803C has a series base resistor to each Darlington pair, thus allowing operation directly with TTL or CMOS operating at supply voltages of 5 V or 3.3 V. The ULN2803C offers solutions to a great many interface needs, including solenoids, relays, lamps, small motors, and LEDs. Applications requiring sink currents beyond the capability of a single output can be accommodated by paralleling the outputs.