ULN2003A

It consists of an array of seven NPN Darlington transistors capable of 500 mA, 50 V output.

It features common-cathode flyback diodes for switching inductive loads (such as servomotors).

[1][2] In the same family are ULN2002A, ULN2004A, as well as ULQ2003A and ULQ2004A, designed for different logic input levels.

The seven Darlington pairs in ULN2003 can operate independently except the common cathode diodes that connect to their respective collectors.

Main specifications: Typical usage of the ULN2003A is in driver circuits for relays, solenoids, lamp and LED displays, stepper motors, logic buffers and line drivers.

ULN2003A pinout
Simplified ULN2003A logical pinout diagram.
Chip die for ULN2003.
A ULN2003 installed in a breakout board to be used as a unipolar stepper motor driver with a 28BYJ stepper motor on the left.