Texas Instruments ULQ2003ATDG4Q1

Overview

ULQ2003ATDG4Q1 from Texas Instruments is an automotive-qualified 7-channel high-voltage Darlington transistor array designed for inductive load switching. It delivers 500mA per channel, supports 50V collector-emitter voltage, integrates common-cathode clamp diodes, and features 2.7kΩ input base resistors for direct TTL/5V CMOS interfacing - used in relay, stepper motor, lamp, and LED driver circuits.

For engineers reviewing the ULQ2003ATDG4Q1 datasheet, ULQ2003ATDG4Q1 pinout, ULQ2003ATDG4Q1 application, or ULQ2003ATDG4Q1 equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, automotive-grade thermal and ESD performance data, and two confirmed alternative parts with functional and application-level distinctions.

Technical Context

The ULQ2003ATDG4Q1 implements seven NPN Darlington pairs in a single monolithic IC, each with integrated 2.7kΩ series base resistor and open-collector output. Its architecture enables direct logic-level drive from 3.3V or 5V GPIO while delivering high sink current (500mA) and clamping inductive kickback via internal common-cathode diodes tied to the COM pin.

It operates across –40°C to +105°C (ULQ2003AT grade), supports 50V absolute max V_CE, exhibits V_CE(sat) ≤1.3V at 200mA, and achieves ESD robustness of ±2000V HBM - all critical for automotive relay and solenoid control where transient immunity and junction temperature stability are non-negotiable.

Key Specifications

Pinout & Package

ULQ2003ATDG4Q1 is supplied in a 16-pin SOIC (D) package measuring 9.90mm × 3.90mm, with gull-wing leads and RoHS-compliant NiPdAu finish. The package supports standard reflow (MSL Level-1, 260°C peak).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ULQ2003ATDG4Q1, ULQ2003AQDRQ1 extends junction temperature capability and adds RoHS compliance for new automotive platforms, while ULN2003A offers identical functionality without qualification overhead - making it suitable only for non-automotive contexts where reliability validation is handled externally.

Availability

ULQ2003ATDG4Q1 is available at Aetrix Electronics and suitable for automotive relay control, stepper actuation, cabin lighting, and LED display driver applications requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ULQ2003ATDG4Q1 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 automotive ICs, with decades of experience in high-reliability power interface solutions.

The ULQ200xA-Q1 product line was developed specifically for automotive body electronics, offering AEC-Q100-qualified Darlington arrays that simplify high-current switching while meeting stringent ESD, thermal, and lifetime requirements.

FAQ

What is the maximum continuous collector current per channel for ULQ2003ATDG4Q1?

The ULQ2003ATDG4Q1 supports 500mA maximum collector current per Darlington channel under recommended operating conditions. This rating applies at T_A = 25°C with proper PCB copper pour; derating is required above 25°C ambient, and simultaneous multi-channel operation must respect total power dissipation limits defined by R_θJA = 87.9°C/W in SOIC package. ULQ2003ATDG4Q1 maintains this capability across its full –40°C to +105°C operating range.

Does ULQ2003ATDG4Q1 require external flyback diodes when driving relays?

No, ULQ2003ATDG4Q1 does not require external flyback diodes when driving relays. It integrates seven common-cathode clamp diodes connected to the COM pin. When COM is tied to the relay coil supply voltage (e.g., +12V), these diodes provide a low-impedance path for inductive kickback energy, protecting the Darlington outputs. ULQ2003ATDG4Q1's internal diode VF is 1.7–2.2V at 350mA, ensuring effective suppression without added components.

What logic families can directly drive ULQ2003ATDG4Q1 inputs?

ULQ2003ATDG4Q1 inputs are directly compatible with TTL and 5V CMOS logic families due to its integrated 2.7kΩ base resistors. It accepts 3.3V or 5V logic-high signals - VI(on) is specified at 2.7V min for 200mA output - and draws ~1.35mA input current at 3.65V. ULQ2003ATDG4Q1 is not optimized for 6–15V CMOS; for those, ULQ2004A-Q1 (10.5kΩ resistor) is recommended instead.

Is ULQ2003ATDG4Q1 pin-compatible with ULN2003A?

Yes, ULQ2003ATDG4Q1 is pin-compatible with ULN2003A: both use identical 16-pin SOIC (D) footprint, pin numbering, and functional mapping (1B–7B, E, COM, 1C–7C). However, ULQ2003ATDG4Q1 adds AEC-Q100 qualification, enhanced ESD (±2000V HBM), tighter parametric screening, and automotive-grade traceability - making it a drop-in replacement in form, fit, and function, but with certified reliability for automotive production.

What is the purpose of the COM pin on ULQ2003ATDG4Q1?

The COM pin on ULQ2003ATDG4Q1 serves as the common cathode node for all seven internal clamp diodes. When driving inductive loads like relays or solenoids, COM must be connected to the positive supply rail of the load (e.g., +12V) to provide a return path for flyback current. For resistive loads such as lamps or LEDs, COM may be left floating or tied to V_CC depending on circuit configuration - ULQ2003ATDG4Q1's COM pin is not a power supply input but a dedicated diode return terminal.