ULN2003 7-channel Darlington transistor array — 500mA, 50V, DIP-16 through-hole

The ULN2003 is a high-voltage, high-current 7-channel Darlington transistor array IC in a DIP-16 through-hole package. Each of the seven channels consists of an NPN Darlington pair with a common-emitter open-collector output, rated at 500mA continuous and 600mA peak per channel. Built-in suppression diodes on each output clamp inductive kickback from relays, solenoids, and motors, eliminating the need for external flyback diodes.

The copper leadframe reduces thermal resistance for improved heat dissipation. The inputs are pinned opposite the outputs to simplify PCB routing, and the inputs are compatible with 5V TTL and CMOS logic levels, making the ULN2003 a direct interface between microcontrollers and high-current loads. The DIP-16 package is breadboard and perfboard compatible, ideal for prototyping.

Key Specifications:

• Part number: ULN2003A (DIP-16 package)
• Number of channels: 7
• Output voltage (V_CE): 50V max
• Output current per channel: 500mA continuous, 600mA peak
• Input voltage compatibility: 5V TTL / CMOS
• Output type: Open-collector NPN Darlington
• Suppression diodes: yes (integrated, one per channel)
• Package: DIP-16 (through-hole)
• Leadframe: Copper (low thermal resistance)
• Operating temperature: −20°C to +85°C

Key Features:

• 7 independent Darlington channels — drive up to 7 separate loads simultaneously
• Integrated flyback diodes — safe driving of relays, solenoids, and inductive loads without external diodes
• TTL/CMOS compatible inputs — direct interface from Arduino, STM32, ESP32, and other microcontrollers
• Open-collector outputs — can switch loads referenced to voltages higher than the logic supply
• Copper leadframe — lower thermal resistance for better heat dissipation at high currents
• DIP-16 through-hole — breadboard and perfboard compatible, ideal for prototyping and hand soldering

Applications:

• Relay driver arrays (5V logic to 12V/24V relay coils)
• Stepper motor driver (unipolar, 4-phase)
• Solenoid and valve driver
• LED and lamp driver arrays
• Printer head driver
• Industrial I/O output expansion

Note: For SMD/surface-mount designs, see ULN2003 SOP-16 variant.