ULN2003AD: 7-Channel Darlington Array Datasheet, Pinout, Pricing, and Alternatives

Quick Answers

The ULN2003AD is a 7-channel high-voltage, high-current Darlington transistor array from Texas Instruments. Each channel sinks 500 mA continuously (600 mA peak) and is rated for 50 V collector-emitter voltage. The device is available in a surface-mount SOIC-16 package, operates from -40°C to +105°C, and is RoHS compliant. As of 2026-08-21, XAIPART shows 99,999 units in stock with a base price of $0.0843 at 1,000-piece quantity and a 1-unit price of $0.1445. This pillar page synthesizes the verified datasheet values, design guidance, drop-in replacements, and market status you need to evaluate the ULN2003AD.

This driver integrates seven open-collector Darlington pairs with common-cathode clamp diodes for inductive-load protection. It is a direct interface between TTL or 5V CMOS logic and high-current loads such as relays, solenoids, stepper motors, and lamps.

Technical Guide

Select the ULN2003AD when you need seven Darlington channels with a 50 V collector-emitter rating and 500 mA continuous current per channel. The 600 mA peak rating covers inrush and switching transients. The open-collector output lets you place the load between a positive supply up to 50 V and the output pin. The common emitter for all channels means you need only one ground connection.

Design-in steps:

• Connect each input pin (IN1-IN7) to your MCU output or other TTL/5V CMOS signal. The device is compatible with TTL and 5V CMOS logic; do not assume 3.3V logic will meet the input threshold.
• Connect the COM pin (pin 9) to the positive supply rail of the inductive load. The built-in clamp diodes conduct from each output to COM, suppressing inductive kickback when the load is switched off.
• Connect the load between the positive supply and the output pin (OUT1-OUT7). For relays and motors, the coil/phase connects from +V to OUTx.
• Connect GND (pin 8) to the system ground.
• Keep the collector-emitter voltage at or below 50 V and the continuous collector current at or below 500 mA per channel.

Pin orientation in the SOIC-16 package: pin 1 IN1, pin 2 IN2, pin 3 IN3, pin 4 IN4, pin 5 IN5, pin 6 IN6, pin 7 IN7, pin 8 GND, pin 9 COM, pin 10 OUT7, pin 11 OUT6, pin 12 OUT5, pin 13 OUT4, pin 14 OUT3, pin 15 OUT2, pin 16 OUT1.

Key verified specifications:

Design Considerations

Each Darlington channel includes a base resistor (2.7 kΩ) and an emitter resistor (3.6 kΩ) to ensure proper biasing and thermal stability. These input resistors allow direct connection to TTL outputs; for 3.3V logic, the input threshold may not be reliably met, so use a level shifter or a Darlington array with a lower input threshold.

For inductive loads, never omit the COM connection. The clamp diodes are only effective when COM is tied to the positive rail. For example, with a 12V relay, connect COM to 12V; with a 24V solenoid, connect COM to 24V. The clamp diode reverse voltage is rated at 50 V, and the forward current is 500 mA, which covers the flyback current from small and medium inductive loads.

Saturation voltage directly affects power dissipation. The typical VCE(sat) is 1.6 V at IC=350 mA. If a single channel carries 350 mA, the saturated transistor dissipates 0.56 W. When multiple channels operate simultaneously, sum each channel's dissipation and keep the total within the package's thermal limits.

Alternatives & Comparison

The verified drop-in alternatives to ULN2003AD are all Texas Instruments parts with the same die and SOIC-16 package:

• ULN2003ADR: same die and package, tape-and-reel packaging variant.
• ULN2003ADRG4: same die and package, RoHS compliant, lead-free finish.
• ULN2003ADRE4: same die and package, RoHS compliant, lead-free finish.

All three are pin-compatible and electrically identical to ULN2003AD. Choose based on packaging and finish requirements.

Summary: For reflow assembly with high-volume manufacturing, ULN2003ADR's tape-and-reel packaging is a precise drop-in. If lead-free finish is a procurement requirement, ULN2003ADRG4 and ULN2003ADRE4 satisfy that constraint.

Industry Insight

The ULN2003AD lifecycle status is active. XAIPART inventory, as of 2026-08-21, shows 99,999 units available with a 1-unit minimum order quantity. This indicates a healthy, readily available supply position. The active lifecycle means Texas Instruments continues to support the part and it is not approaching end-of-life.

Pricing tiers from the XAIPART verified database (as of 2026-08-21):

Buyers should note that the ULN2003AD is not AEC-Q100 qualified, according to the verified FAQ data. For automotive applications, the FAQ recommends considering the AEC-Q100-qualified variant ULN2003ADR-Q1. That distinction is important for procurement in automotive supply chains.

Trends & Outlook

The ULN2003AD remains a workhorse for low-cost, high-current sink applications. The 50 V / 500 mA rating still covers most industrial 12V and 24V loads, and the SOIC-16 package keeps it compatible with modern surface-mount assembly lines. The active lifecycle and large XAIPART stock suggest continued demand for this part in relay boards, stepper motor drivers, and industrial I/O modules.

Buyers should watch two trends:

• Logic-level migration: The device is specified for TTL and 5V CMOS. As MCUs move to 3.3V, designers must either ensure the GPIO voltage is high enough to meet the ULN2003AD input threshold or add a level-shift stage.
• Packaging substitutions: The ULN2003ADR tape-and-reel variant is preferred for automated assembly, and the lead-free finish variants (ULN2003ADRG4/ULN2003ADRE4) satisfy RoHS-focused BOMs.

Because all four variants share the same die and package, stocking one variant as a substitute for the others mitigates supply risk without requalifying the PCB.