ULN2003 7 Darlington Transistor Array IC DIP-16

ULN2003 7 Darlington Transistor Array IC DIP-16 is a high-voltage, high-current transistor array widely recognized as a critical interface component for driving inductive loads using low-power logic signals. This integrated circuit contains seven NPN Darlington transistor pairs, each featuring a common-cathode clamp diode for switching inductive loads such as relays, solenoids, and stepper motors. Consequently, it enables microcontrollers (operating at 5V or 3.3V) to safely control devices requiring much higher voltage or current without complex driver stages. Furthermore, its convenient DIP-16 package and robust design make the ULN2003 an industry standard for reliable power amplification in embedded systems. Therefore, utilize the ULN2003 to simplify your design when you need to switch multiple medium-power loads directly from logic outputs.

Key Features:

• Seven Darlington Pairs: Contains seven independent high-gain Darlington transistor stages, allowing the control of up to seven separate loads simultaneously.
• High Output Current: Each channel can sink continuous collector currents up to 500 mA, although you can parallel channels to achieve higher total current handling capability.
• High Output Voltage: Supports a maximum output collector voltage (V_CE(max)) of 50 V, making it compatible with various standard relay and motor coils.
• Integrated Suppression Diodes: Each Darlington pair incorporates an internal common-cathode clamp diode to protect the transistors from transient flyback voltage generated by inductive loads.
• TTL/CMOS Compatible Input: The input stage operates efficiently with standard 5V TTL and CMOS logic levels, simplifying interfacing with microcontrollers.

Technical Specifications:

• Number of Channels: 7
• Collector Output Voltage (V_CE(max)): 50 V
• Continuous Collector Current (I_C): 500 mA per channel (600 mA peak)
• Total Power Dissipation: 2.25 W (at T_A=25°C)
• Input Voltage (V_in): Typically 5 V TTL/CMOS compatible
• HFE (Current Gain): Very high due to Darlington configuration (≥ 1000)
• Operating Temperature Range: −20°C to +85°C (Commercial/Industrial)

Mechanical Specifications:

• Package Type: DIP-16 (Dual In-line Package)
• Mounting: Through-Hole Technology (THT)
• Lead Finish: Lead-free plating
• Material: Plastic Encapsulation

Dimensions:

• Body Length: ≈ 19.3 mm
• Body Width: ≈ 6.4 mm
• Pin Pitch (Between pins): 2.54 mm (0.1 inch)
• Row Spacing (Between rows): 7.62 mm (0.3 inch)
• Total Height: ≈ 4.5 mm (Seated height)

Pinout and Wiring:

• Pins 1-7 (Input 1 to Input 7): Connect these pins directly to the digital output pins of your microcontroller or logic device.
• Pins 10-16 (Output 1 to Output 7): Connect these pins to the negative (ground) side of your high-power loads (e.g., relay coil, motor winding).
• Pin 8 (GND): Connect to the circuit ground reference (0 V).
• Pin 9 (COM): Connect this pin to the positive supply voltage of the load (V_LOAD) to enable the internal clamping diodes for inductive load protection. If the load is resistive, you may leave this pin unconnected.

Datasheet Reference:

• Download Texas Instruments ULN2003A Datasheet

Commonly Used in:

• Stepper Motor Drivers: The seven channels are often used in pairs to drive bi-polar or unipolar stepper motors.
• Relay Boards: It serves as the primary driver stage, safely switching the current required by relay coils.
• Industrial Control Systems: Used to interface low-voltage PLC outputs with higher voltage solenoids and indicators.

Applications:

• Driving Solenoids and Valves: Switches high-current DC solenoids found in locking mechanisms and fluid control valves.
• Driving LEDs and Displays: Controls large LED matrices or multiple common-cathode LED displays requiring high sink current.
• Peripheral Switching: Controls buzzers, horns, and small DC motors that exceed the current capacity of a standard microcontroller pin.

Equivalent Models:

• ULN2004A: Functionally identical to the ULN2003A, however, it is optimized for high-level logic families (CMOS/PMOS) with a higher input trigger voltage.
• ULQ2003A: A variation typically manufactured by multiple vendors, maintaining the same core specifications and pinout.
• TD62003APG (Toshiba): A direct cross-reference and pin-compatible equivalent often used as a direct replacement.

Package Includes:

• 1 x ULN2003 7 Darlington Transistor Array IC DIP-16