ULN2003AD - 7-Channel Darlington Driver | Texas Instruments
MPN: ULN2003AD β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.45 | $0.45 |
| 10 | $0.38 | $3.80 |
| 100 | $0.3 | $30.00 |
| 500 | $0.25 | $125.00 |
| 1,000 | $0.2 | $200.00 |
Drop-in alternatives for ULN2003AD β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ULN2003ADR
β Drop-Inπ Reference alternative (not in catalog)
ULN2003ADRG4
β Drop-Inπ Reference alternative (not in catalog)
ULN2003ADRE4
β Drop-Inπ Reference alternative (not in catalog)
ULN2003AD Maximum Ratings & Electrical Characteristics
| Number of Channels | 7 |
| Collector-Emitter Voltage (VCE) | 50 V |
| Collector Current (IC) per Channel | 500 mA (continuous), 600 mA (peak) |
| Input Voltage (VIN) | 30 V (max) |
| Base Current (IB) | 25 mA (max) |
| Saturation Voltage (VCE(sat)) | 1.6 V (typical at IC=350 mA) |
| Clamp Diode Reverse Voltage | 50 V |
| Clamp Diode Forward Current | 500 mA |
| Input Resistance | 2.7 kΞ© (base), 3.6 kΞ© (emitter) |
| Operating Temperature Range | -40Β°C to +105Β°C |
| Package | SOIC-16 (D) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Logic Compatibility | TTL, 5V CMOS |
| Output Type | Open Collector |
ULN2003AD Pin Configuration
| Pin 1 | IN1 β Input channel 1 |
| Pin 2 | IN2 β Input channel 2 |
| Pin 3 | IN3 β Input channel 3 |
| Pin 4 | IN4 β Input channel 4 |
| Pin 5 | IN5 β Input channel 5 |
| Pin 6 | IN6 β Input channel 6 |
| Pin 7 | IN7 β Input channel 7 |
| Pin 8 | GND β Ground |
| Pin 9 | COM β Common cathode for clamp diodes |
| Pin 10 | OUT7 β Output channel 7 |
| Pin 11 | OUT6 β Output channel 6 |
| Pin 12 | OUT5 β Output channel 5 |
| Pin 13 | OUT4 β Output channel 4 |
| Pin 14 | OUT3 β Output channel 3 |
| Pin 15 | OUT2 β Output channel 2 |
| Pin 16 | OUT1 β Output channel 1 |
Safe Operating Area (SOA) & Thermal Characteristics
No official SOA curve available for this component. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.
Typical Applications
ULN2003AD is suitable for 6 applications: Relay Driver, Stepper Motor Driver, Solenoid Driver, Lamp Driver, Industrial Control, Consumer Electronics.
Relay Driver
The ULN2003AD is ideal for driving relays in industrial control and home automation systems. Each channel can sink up to 500 mA, sufficient for most small and medium relays. The built-in clamp diodes protect the driver from inductive kickback when the relay coil is de-energized. In a typical application, the relay coil is connected between the positive supply and the output pin, with the COM pin tied to the same supply. The input is driven by a microcontroller or logic gate, and the Darlington pair provides high current gain, allowing direct interfacing without additional transistors. The low saturation voltage (1.6 V at 350 mA) minimizes power dissipation, and the 50 V collector-emitter rating supports 12V and 24V relay coils. For multiple relays, the seven channels can drive up to seven relays, simplifying PCB layout and reducing component count. The device's thermal performance is adequate for continuous operation at moderate currents, but for high-duty-cycle applications, ensure the total power dissipation is within the package limits.
Recommended
Stepper Motor Driver
The ULN2003AD is widely used to drive unipolar stepper motors in 3D printers, CNC machines, and robotics. Each motor phase is connected to one of the seven channels, with the common center tap connected to the positive supply. The Darlington array provides the high current required by stepper motor coils, typically 300-500 mA per phase. The built-in clamp diodes are essential for suppressing the inductive spikes generated when the phase is switched off, preventing damage to the driver. The input can be driven directly by a stepper motor controller IC or a microcontroller with a simple transistor interface. The 50 V collector-emitter rating allows operation with 12V or 24V motors. The low saturation voltage reduces power loss in the driver, improving efficiency. For bipolar stepper motors, an H-bridge driver is required, but the ULN2003AD is specifically suited for unipolar configurations. The device's seven channels allow driving a 4-phase motor with three channels to spare for other functions.
Recommended
Solenoid Driver
The ULN2003AD is suitable for driving solenoids in vending machines, door locks, and industrial automation. Solenoids typically require a high current pulse to actuate, and the ULN2003AD can provide up to 500 mA per channel. The integrated clamp diodes protect the driver from the high-voltage spike generated when the solenoid is de-energized. In a typical application, the solenoid is connected between the positive supply and the output pin, with the COM pin tied to the supply. The input is driven by a PLC or microcontroller. The 50 V collector-emitter rating supports 12V and 24V solenoids. The device's high current gain allows direct interfacing with low-current logic outputs. For solenoids requiring more than 500 mA, two channels can be paralleled to increase current capability. The thermal performance is adequate for intermittent operation, but for continuous duty, consider the power dissipation and add heatsinking if necessary.
Recommended
Lamp Driver
The ULN2003AD can drive incandescent lamps and LED arrays in automotive and industrial applications. Each channel can sink up to 500 mA, sufficient for small lamps and LED strips. The open-collector output allows the lamp to be connected between the positive supply and the output pin. The built-in clamp diodes are not required for resistive loads but are present for inductive loads. The input is compatible with TTL and 5V CMOS logic, making it easy to interface with microcontrollers. The 50 V collector-emitter rating supports 12V and 24V lamp systems. The low saturation voltage minimizes power dissipation in the driver, improving efficiency. For LED arrays, a current-limiting resistor is required in series with each LED string. The device's seven channels can drive up to seven lamps or LED strings, simplifying the driver circuit. The thermal performance is adequate for moderate currents, but for high-current lamps, ensure the total power dissipation is within the package limits.
Recommended
Industrial Control
The ULN2003AD is used in industrial control systems for interfacing logic-level signals to high-current actuators such as contactors, valves, and motors. The device provides a robust interface between PLCs or microcontrollers and industrial loads. The 50 V collector-emitter rating and 500 mA current capability are suitable for many industrial loads. The built-in clamp diodes protect against inductive transients from contactor coils and motor windings. The input is compatible with TTL and 5V CMOS logic, allowing direct connection to PLC output modules. The SOIC-16 package is compact and suitable for PCB mounting in control cabinets. The device's seven channels allow driving multiple actuators from a single IC, reducing component count and PCB area. The operating temperature range of -40Β°C to +105Β°C ensures reliable operation in harsh industrial environments. For high-reliability applications, consider the automotive-grade variant ULN2003ADR-Q1.
Recommended
Consumer Electronics
The ULN2003AD is used in consumer electronics for driving small motors, relays, and LEDs in appliances, toys, and gaming peripherals. The device's low cost and ease of use make it popular in hobbyist and DIY projects. The 500 mA current capability is sufficient for small DC motors and relays. The built-in clamp diodes protect against inductive spikes from motors. The input is compatible with 5V logic from microcontrollers like Arduino. The SOIC-16 package is suitable for compact PCB designs. The device's seven channels allow driving multiple loads from a single IC. The low saturation voltage minimizes power dissipation, extending battery life in portable devices. The operating temperature range is suitable for consumer environments. For applications requiring higher current, the ULN2803A (8 channels, 500 mA) or ULN2004A (higher input voltage) can be considered.
Recommended
Recommended Products Summary
Engineering reference data for ULN2003AD β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ULN2003ADR | ULN2003ADRG4 | ULN2003ADRE4 |
|---|---|---|---|---|
| Package | SOIC-16 (D) | SOIC-16 (D) - same | SOIC-16 (D) - same | SOIC-16 (D) - same |
| Number of Channels | 7 | 7 | 7 | 7 |
| Collector-Emitter Voltage | 50 V | 50 V | 50 V | 50 V |
| Collector Current per Channel | 500 mA | 500 mA | 500 mA | 500 mA |
| Saturation Voltage | 1.6 V (typical) | 1.6 V (typical) | 1.6 V (typical) | 1.6 V (typical) |
| Clamp Diodes | Yes | Yes | Yes | Yes |
| RoHS Compliant | Yes | Yes | Yes | Yes |
| Automotive Grade | No | No | No | No |
Key Differentiators
- Same SOIC-16 package with tape and reel packaging (vs ULN2003AN (DIP-16))
- Identical electrical specifications to ULN2003ADR (vs ULN2003ADR)
- RoHS compliant and lead-free (vs ULN2003AN (DIP-16))
Design Notes
The ULN2003AD can dissipate significant power when driving multiple channels at high current. For example, driving 7 channels at 500 mA with a saturation voltage of 1.6 V results in a total power dissipation of 5.6 W. The SOIC-16 package has a thermal resistance of approximately 73Β°C/W (theta_JA), so the junction temperature rise would be 409Β°C above ambient, which is unacceptable. Ensure adequate PCB copper area or use a heatsink for high-current applications. For continuous operation, keep the total power dissipation below 1 W per package.
Place the COM pin (pin 9) connection to the positive supply rail with a low-impedance trace, as it carries the clamp diode current during inductive switching. Use a 0.1 Β΅F decoupling capacitor near the VCC pin of the load supply to suppress transients. For high-current outputs, use wide traces or copper pours to minimize voltage drop and heat generation. Ensure the GND pin (pin 8) has a solid connection to the ground plane.
Do not forget to connect the COM pin (pin 9) to the positive supply rail when driving inductive loads. If left floating, the clamp diodes will not function, and the inductive kickback can damage the output transistors. Also, ensure the input voltage does not exceed 30 V, and the collector-emitter voltage does not exceed 50 V. For 3.3V logic, use a level shifter or a Darlington array with lower input threshold, as the ULN2003AD is designed for 5V TTL logic.
Compliance Information
RoHS compliant per TI product page. Not AEC-Q100 qualified - choose ULN2003ADR-Q1 for automotive.
