Diodes Incorporated ULN2002AD16-U

Overview

ULN2002AD16-U from Diodes Incorporated is a high-voltage, high-current Darlington transistor array containing seven open-collector NPN pairs, each rated for 500mA continuous collector current and 50V output voltage, with integrated clamp diodes for inductive load suppression - used in relay and solenoid driver circuits operating from 14V to 25V pMOS logic.

For engineers reviewing the ULN2002AD16-U datasheet, ULN2002AD16-U pinout, ULN2002AD16-U application, or ULN2002AD16-U equivalent, this device is selected for robust low-side switching of industrial actuators, where input compatibility with 14–25V pMOS logic, thermal derating at +105°C ambient, and SO-16 package layout efficiency are critical design factors.

Technical Context

The ULN2002A integrates seven independent Darlington pairs with on-chip base resistors (7.2kΩ), enabling direct drive from pMOS logic without external biasing. Each channel features a common-emitter open-collector output with a shared cathode clamp diode network connected to the COM pin.

Its input threshold is specified up to 13V VI(ON) at IC = 300mA, supporting 14–25V logic families, while VCE(SAT) remains ≤1.6V at 350mA with 500µA input drive - ensuring low conduction loss in high-current switching applications.

Key Specifications

Pinout & Package

ULN2002AD16-U is housed in a standard SO-16 (Small Outline, 16-pin) package with 1.27mm pitch, 9.9mm × 3.9mm body, and 1.26mm max height - compatible with automated SMT assembly and IPC-7351B land patterns.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ULN2003AD16-U and ULN2004AD16-U, the ULN2002AD16-U uniquely supports 14–25V pMOS logic directly, offering highest input voltage tolerance and lowest risk of false triggering in noisy industrial environments - making it the only choice for legacy programmable logic controller (PLC) output stage interfacing.

Availability

ULN2002AD16-U is available at Aetrix Electronics and suitable for industrial automation, HVAC control systems, and point-of-sale thermal printer designs requiring stable component supply across multi-year production cycles.

Supply support for ULN2002AD16-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 devices, with manufacturing certified to IATF 16949 and product compliance to RoHS, REACH, and AEC-Q standards.

The ULN2002A belongs to Diodes' high-voltage Darlington array product line, engineered specifically for industrial actuator interface - balancing ruggedness, integration, and ease of layout in space-constrained control modules.

FAQ

What logic families can directly drive ULN2002AD16-U without external resistors?

The ULN2002AD16-U is designed for 14V–25V pMOS logic families. Its input structure includes internal 7.2kΩ base resistors, allowing direct connection to pMOS outputs without external biasing. It is not compatible with standard 3.3V or 5V TTL/CMOS logic due to insufficient input voltage for guaranteed turn-on - attempting such use results in marginal or non-functional switching.

How should the COM pin be connected when driving inductive loads?

The COM pin must be connected to the positive supply rail of the inductive load (e.g., +24V for a relay coil), not to ground or VCC of the logic side. This ties the cathodes of all seven internal clamp diodes to the load's supply, allowing back-EMF current to recirculate safely through the diode during turn-off - preventing voltage spikes that could damage upstream drivers or cause EMI.

Can multiple ULN2002AD16-U outputs be paralleled for higher current per channel?

No - paralleling outputs is not recommended. The Darlington pairs have inherent V_BE mismatches causing uneven current sharing, which may lead to thermal runaway in one channel. For >500mA loads, use external discrete transistors or dedicated high-current drivers; the ULN2002A is rated strictly for 500mA per channel with appropriate thermal derating.

Does ULN2002AD16-U support PWM operation, and what is its maximum usable frequency?

Yes - ULN2002AD16-U supports PWM with typical propagation delays of 0.25–1µs. At 100% duty cycle, thermal limits govern usage; for pulsed operation, maximum usable frequency depends on duty cycle and ambient temperature. At 50% duty cycle and +70°C ambient, frequencies up to 10kHz maintain safe junction temperature, assuming proper PCB copper area for heat dissipation.