ULN2003A - High-Voltage, High-Current Darlington Transistor Array

Overview

The ULN2003A is a high-voltage, high-current Darlington transistor array consisting of seven NPN Darlington pairs capable of handling load currents up to 500 mA per channel. This device features common-cathode clamp diodes for switching inductive loads, making it particularly suitable for interfacing between low-level logic circuitry and multiple peripheral power loads.

Designed for general-purpose switching applications, the ULN2003A offers compatibility with TTL, DTL, PMOS, or CMOS logic levels. Each channel is rated at 95V, with all outputs protected by suppression diodes for handling inductive load transients. The device is available in both dual in-line (DIP) and small-outline (SOIC) packages.

Features

• Seven Darlington transistor arrays with common emitters
• Output current rating of 500 mA per channel (600 mA peak)
• Output voltage rating of 95V
• Integrated suppression diodes for inductive load switching
• Inputs compatible with various logic families:
  • TTL (5V)
  • DTL
  • PMOS
  • CMOS
• Available in 16-pin configurations:
  • Dual in-line plastic package (ULN2003A)
  • Small-outline IC package (ULN2003L)
• Inputs pinned opposite outputs to simplify board layout
• High noise immunity

Applications

The ULN2003A finds extensive use in various electronic systems requiring high-current switching capabilities:

• Relay drivers
• Stepper motor controllers
• Lamp drivers
• Display drivers (LED, incandescent)
• Logic buffers
• Hammer drivers
• Industrial control systems
• Automotive applications
• Peripheral drivers for microcontrollers

Electrical Characteristics

Absolute Maximum Ratings

• Output Voltage (V_CE): 95V
• Output Current (I_C): 500 mA per channel
• Peak Output Current (I_C peak): 600 mA per channel
• Input Voltage (V_IN): 30V
• Power Dissipation (P_D): 2.25W (DIP), 1.4W (SOIC)
• Operating Temperature Range: -20°C to +85°C
• Storage Temperature Range: -65°C to +150°C

Electrical Specifications (T_A = 25°C unless otherwise noted)

• Input Clamp Voltage (V_IK): 1.5V max at I_IN = 3.0 mA
• Input Current (I_IN): 1.0 mA max at V_IN = 3.85V
• Output Saturation Voltage (V_CE(sat)):
  • 1.1V max at I_C = 200 mA, I_B = 0.25 mA
  • 1.6V max at I_C = 350 mA, I_B = 0.5 mA
• Output Leakage Current (I_CEO): 100 μA max at V_CE = 50V
• Output Clamp Diode Forward Voltage (V_F): 1.6V max at I_F = 350 mA
• Current Gain (h_FE): 1000 min at I_C = 350 mA

Package Information

16-Pin Dual In-Line Package (DIP)

• Package Designation: ULN2003A
• Package Type: PDIP-16
• Dimensions: 19.30mm x 6.35mm (body)
• Pin Spacing: 2.54mm (100 mil) between pins
• Row Spacing: 7.62mm (300 mil) between rows
• Lead Material: Copper alloy
• Lead Finish: Matte tin
• Moisture Sensitivity Level (MSL): MSL 1

16-Pin Small Outline IC Package (SOIC)

• Package Designation: ULN2003L
• Package Type: SOIC-16
• Dimensions: 9.90mm x 3.90mm (body)
• Pin Spacing: 1.27mm (50 mil)
• Lead Pitch: 1.27mm
• Lead Material: Copper alloy
• Lead Finish: Matte tin
• Moisture Sensitivity Level (MSL): MSL 1

Pin Configuration

The ULN2003A features the following pinout configuration:

• Pin 1: Input 1
• Pin 2: Input 2
• Pin 3: Input 3
• Pin 4: Input 4
• Pin 5: Input 5
• Pin 6: Input 6
• Pin 7: Input 7
• Pin 8: Ground
• Pin 9: Common (for clamp diodes)
• Pin 10: Output 7
• Pin 11: Output 6
• Pin 12: Output 5
• Pin 13: Output 4
• Pin 14: Output 3
• Pin 15: Output 2
• Pin 16: Output 1

Thermal Characteristics

• Thermal Resistance, Junction-to-Air (θ_JA):
  • DIP Package: 60°C/W
  • SOIC Package: 95°C/W
• Thermal Resistance, Junction-to-Case (θ_JC):
  • DIP Package: 25°C/W
  • SOIC Package: 40°C/W

Design Considerations

When implementing the ULN2003A in circuit designs, several important factors should be considered:

• For inductive loads, connect the common pin (Pin 9) to the positive supply voltage to provide a return path for the clamp diodes
• Ensure proper heat sinking when operating multiple channels simultaneously or at high currents
• The device can drive loads directly connected to the positive supply (high-side switching) when