COM

Output C

E

Input B

2.7

NŸ

7.2

NŸ

3

NŸ

COM

Output C

E

Input B

10.5

NŸ

7.2

NŸ

3

NŸ

COM

Output C

E

Input B

10.5

NŸ

7.2

NŸ

3

NŸ

7 V

12

ULN2002A, ULN2003A, ULN2003AI

ULQ2003A, ULN2004A, ULQ2004A

SLRS027O – DECEMBER 1976 – REVISED JANUARY 2016

www.ti.com

Product Folder Links: ULN2002A ULN2003A ULN2003AI ULQ2003A ULN2004A ULQ2004A

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Copyright © 1976–2016, Texas Instruments Incorporated

8 Detailed Description

8.1 Overview

This standard device has proven ubiquity and versatility across a wide range of applications. This is due to

integration of 7 Darlington transistors of the device that are capable of sinking up to 500 mA and wide GPIO

range capability.

The ULN2003A device comprises seven 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 ULN2003A device 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 ULN2003A

device 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 may be accommodated by

paralleling the outputs.

This device can operate over a wide temperature range (–40°C to 105°C).

8.2 Functional Block Diagrams

All resistor values shown are nominal. The collector-emitter diode is a parasitic structure and should not be used

to conduct current. If the collectors go below GND, an external Schottky diode should be added to clamp

negative undershoots.

Figure 19. ULN2002A Block Diagram

Figure 20. ULN2003A, ULQ2003A and ULN2003AI

Block Diagram

Figure 21. ULN2004A and LQ2004A Block Diagram