SLRS027R December   1976  – February 2024 ULN2002A , ULN2003A , ULN2003AI , ULN2004A , ULQ2003A , ULQ2004A

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1  Absolute Maximum Ratings
    2. 5.2  ESD Ratings
    3. 5.3  Recommended Operating Conditions
    4. 5.4  Thermal Information
    5. 5.5  Electrical Characteristics: ULN2002A
    6. 5.6  Electrical Characteristics: ULN2003A and ULN2004A
    7. 5.7  Electrical Characteristics: ULN2003AI
    8. 5.8  Electrical Characteristics: ULN2003AI
    9. 5.9  Electrical Characteristics: ULQ2003A and ULQ2004A
    10. 5.10 Switching Characteristics: ULN2002A, ULN2003A, ULN2004A
    11. 5.11 Switching Characteristics: ULN2003AI
    12. 5.12 Switching Characteristics: ULN2003AI
    13. 5.13 Switching Characteristics: ULQ2003A, ULQ2004A
    14. 5.14 Typical Characteristics
  7. 6 Parameter Measurement Information
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagrams
    3. 7.3 Feature Description
    4. 7.4 Device Functional Modes
      1. 7.4.1 Inductive Load Drive
      2. 7.4.2 Resistive Load Drive
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Drive Current
        2. 8.2.2.2 Low-Level Output Voltage
        3. 8.2.2.3 Power Dissipation and Temperature
      3. 8.2.3 Application Curves
    3. 8.3 System Examples
  10. 9 Power Supply Recommendations
  11. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  12. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Related Links
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Support Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  13. 12Revision History
  14. 13Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • NS|16
  • N|16
  • D|16
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.3 Feature Description

Each channel of the ULN2003A device consists of Darlington connected NPN transistors. This connection creates the effect of a single transistor with a very high-current gain (β2). This can be as high as 10,000 A/A at certain currents. The very high β allows for high-output current drive with a very low input current, essentially equating to operation with low GPIO voltages.

The GPIO voltage is converted to base current through the 2.7-kΩ resistor connected between the input and base of the predriver Darlington NPN. The 7.2-kΩ and 3-kΩ resistors connected between the base and emitter of each respective NPN act as pulldowns and suppress the amount of leakage that may occur from the input.

The diodes connected between the output and COM pin is used to suppress the kick-back voltage from an inductive load that is excited when the NPN drivers are turned off (stop sinking) and the stored energy in the coils causes a reverse current to flow into the coil supply through the kick-back diode.

In normal operation the diodes on base and collector pins to emitter will be reversed biased. If these diodes are forward biased, internal parasitic NPN transistors will draw (a nearly equal) current from other (nearby) device pins.