Diodes Incorporated ULN2003AD16-U

Overview

ULN2003AD16-U from Diodes Incorporated is a 7-channel high-voltage, high-current Darlington transistor array in SO-16 (Type SM) package, rated for 500mA per channel and 50V collector-emitter voltage, with integrated clamp diodes for inductive load driving and TTL/CMOS-compatible inputs. It serves as a logic-level interface to drive relays, solenoids, and DC motors in industrial control and automation systems.

For engineers reviewing the ULN2003AD16-U datasheet, ULN2003AD16-U pinout, ULN2003AD16-U application, or ULN2003AD16-U equivalent, key selection criteria include per-channel current capability (500mA), input compatibility (5V TTL/CMOS), output clamp diode integration, saturation voltage (≤1.6V at 350mA), and thermal resistance (63.0°C/W junction-to-ambient).

Technical Context

The ULN2003AD16-U integrates seven independent Darlington pairs with on-chip base resistors (2.7kΩ) optimized for 5V logic drive, enabling direct connection to microcontroller GPIOs without external biasing. Each channel features an open-collector output and shares a common cathode clamp diode network connected to pin 9 (COM).

Its architecture supports simultaneous multi-channel switching with defined thermal derating: maximum total emitter current is –2.5A, and continuous operation at full 500mA per channel requires ambient temperature ≤70°C when all seven outputs are active. Input threshold is specified at VI(ON) ≤3.0V (IC = 300mA), ensuring reliable turn-on across –40°C to +105°C.

Key Specifications

Pinout & Package

ULN2003AD16-U is housed in a 16-pin Small Outline (SO-16 Type SM) package with 1.27mm pitch, 1.75mm max height, and matte tin-plated leads compliant with J-STD-020 Level 3 moisture sensitivity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Darlington array applications.

Compared with ULN2003AD16-U, ULN2003A-S16-13 offers identical performance in standardized packaging, while ULN2003D16 trades lower input drive strength for reduced quiescent current - making the former ideal for volume production and the latter for low-power CMOS systems.

Availability

ULN2003AD16-U is available at Aetrix Electronics and suitable for industrial automation, embedded motion control, and electromechanical interface applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for ULN2003AD16-U includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Diodes Incorporated is a global semiconductor company specializing in discrete, analog, and mixed-signal ICs, with manufacturing certified to IATF 16949 and products qualified to AEC-Q100/101 standards.

The ULN2003A series belongs to Diodes' high-voltage interface portfolio, designed specifically for robust logic-to-load bridging in industrial, appliance, and building automation systems where reliability under inductive stress is critical.

FAQ

What is the maximum continuous current per channel at 85°C ambient?

At TA = +85°C, the ULN2003AD16-U supports 350mA per channel continuously when operating within its derated thermal envelope. This is derived from the datasheet's "Maximum Collector Current vs. Duty Cycle" curve and θJA = 63.0°C/W, assuming single-channel operation and adequate PCB copper area for heat spreading.

Can ULN2003AD16-U drive a 12V, 400mA relay coil directly?

Yes - the device is rated for 500mA per channel at VCE = 50V, and typical VCE(SAT) is ≤1.1V at 200mA and ≤1.3V at 350mA. With a 12V supply and 400mA load, power dissipation remains within safe limits (≤0.52W per channel), provided ambient temperature stays below 70°C for sustained operation.

Is a pull-up resistor required on the COM pin?

No - the COM pin connects to the cathodes of all internal clamp diodes and must be tied directly to the positive supply rail of the inductive load (e.g., +12V or +24V). No external pull-up is needed or used; incorrect connection (e.g., leaving COM floating or grounding it) disables flyback protection and risks device failure.

Does ULN2003AD16-U support PWM motor speed control?

Yes - its switching characteristics (tPLH/tPHL ≤10µs over –40°C to +105°C) support PWM frequencies up to 50kHz for small DC motors. However, thermal limits apply: at 100% duty cycle and 500mA, junction temperature rise must be managed via PCB layout or forced air, especially with multiple channels active.