Texas Instruments ULQ2003ADRG4

Overview

ULQ2003ADRG4 from Texas Instruments is a 7-channel high-voltage, high-current NPN Darlington transistor array optimized for inductive load switching. It delivers 500mA per channel, supports 50V collector-emitter voltage, integrates common-cathode clamp diodes, features 2.7kΩ input base resistors for direct TTL/5V CMOS compatibility, and operates across –40°C to +85°C ambient temperature - widely deployed in relay and stepper motor control circuits.

For engineers reviewing the ULQ2003ADRG4 datasheet, ULQ2003ADRG4 pinout, ULQ2003ADRG4 application, or ULQ2003ADRG4 equivalent, key selection criteria include verified 500mA sink capability per channel, integrated flyback diode functionality, SOIC-16 package thermal performance (R_θJA = 88.6°C/W), and confirmed operation with 3.3V/5V logic inputs without external biasing.

Technical Context

The ULQ2003ADRG4 implements seven independent Darlington pairs with internal 2.7kΩ series base resistors, enabling direct interface with standard logic families. Each channel provides open-collector outputs with integrated common-cathode clamp diodes tied to the COM pin for inductive kickback suppression.

It operates as a logic-level-controlled current sink: input logic high (≥2.7V) enables conduction; input low disables output. The device requires no external pull-up on outputs when driving inductive loads (COM connected to load supply), but needs external pull-ups for resistive loads or logic-level translation.

Key Specifications

Pinout & Package

ULQ2003ADRG4 is housed in a 16-pin SOIC (D) package measuring 9.90mm × 3.91mm, with standard 1.27mm pitch and gull-wing leads. Thermal resistance is R_θJA = 88.6°C/W, supporting moderate-power continuous operation with minimal heatsinking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ULN2003ADR, ULQ2003ADRG4 offers 15°C higher maximum ambient rating for thermally demanding enclosures; compared with ULQ2003AIPWR, it delivers 25.5°C/W lower junction-to-ambient thermal resistance in the SOIC package - enabling higher sustained current per channel without thermal throttling.

Availability

ULQ2003ADRG4 is available at Aetrix Electronics and suitable for relay control, stepper motor actuation, and industrial lamp driving requiring stable component supply across production lifecycles.

Supply support for ULQ2003ADRG4 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and connectivity technologies with over 90 years of innovation in industrial and automotive electronics.

The ULQ2003ADRG4 belongs to TI's legacy ULx200x Darlington array product line, engineered specifically for robust, low-cost, high-current logic interfacing in industrial control, appliance, and automation systems where reliability under inductive stress is critical.

FAQ

What is the maximum continuous current per channel for ULQ2003ADRG4?

The ULQ2003ADRG4 supports 500mA maximum collector current per channel under recommended operating conditions. This rating assumes proper PCB thermal design and adherence to the SOIC-16 package's thermal limits (R_θJA = 88.6°C/W). Derating is required at elevated ambient temperatures or with multiple channels active simultaneously - refer to Figure 5-4 in the datasheet for duty-cycle–current curves.

Does ULQ2003ADRG4 require external flyback diodes when driving relays?

No, ULQ2003ADRG4 does not require external flyback diodes when driving relays. It integrates seven common-cathode clamp diodes connected to the COM pin. To enable flyback protection, tie the COM pin to the same positive supply rail as the relay coil - this provides a low-impedance path for inductive energy recovery during turn-off.

Can ULQ2003ADRG4 interface directly with 3.3V microcontrollers?

Yes, ULQ2003ADRG4 interfaces directly with 3.3V microcontrollers. Its 2.7kΩ internal input resistors ensure sufficient base drive at 3.3V logic-high levels (typically delivering ~1.2mA input current), meeting the VI(on) threshold of 2.7V min at IC = 300mA. No level-shifting or external biasing is needed for standard 3.3V CMOS outputs.

What is the purpose of the E pin (Pin 8) on ULQ2003ADRG4?

The E pin (Pin 8) is the common emitter connection for all seven Darlington pairs in ULQ2003ADRG4. It must be connected to the system ground or low-side reference potential. Unlike the COM pin (which serves the clamp diodes), E establishes the emitter reference for transistor conduction - incorrect grounding of E will prevent any channel from turning on.

How does ULQ2003ADRG4 differ from ULN2003ADR in terms of temperature rating?

ULQ2003ADRG4 is rated for operation from –40°C to +85°C ambient temperature, whereas ULN2003ADR is specified only from –40°C to +70°C. This +15°C extended upper limit makes ULQ2003ADRG4 suitable for sealed industrial enclosures or outdoor-mounted control units where internal ambient may exceed 70°C under solar loading or proximity to heat sources.