Texas Instruments ULQ2003ATDQ1

Overview

ULQ2003ATDQ1 from Texas Instruments is an automotive-qualified 7-channel high-voltage Darlington transistor array with 500mA per channel sink capability, 50V output rating, integrated common-cathode clamp diodes, and 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 ULQ2003ATDQ1 datasheet, ULQ2003ATDQ1 pinout, ULQ2003ATDQ1 application, or ULQ2003ATDQ1 equivalent, key selection criteria include its AEC-Q100 qualification, −40°C to 105°C operating range, open-collector Darlington architecture with flyback protection, and SOIC-16 package compatibility with legacy ULN2003A layouts.

Technical Context

The ULQ2003ATDQ1 integrates seven NPN Darlington pairs sharing a common emitter (Pin 8) and common cathode clamp node (Pin 9), enabling simultaneous inductive load switching with internal energy recirculation. Each channel features a 2.7kΩ series base resistor and exhibits typical V_CE(sat) of 1.0–1.4V at 100–350mA collector current.

It operates as a logic-level-controlled high-side grounded, low-side switched driver: inputs accept 3.3V/5V logic signals, outputs sink up to 500mA per channel into loads tied to positive supply via COM, and clamp diodes protect against inductive kickback when driving relays or solenoids.

Key Specifications

Pinout & Package

ULQ2003ATDQ1 is supplied in a 16-pin SOIC (D) package measuring 9.90mm × 3.90mm, with gull-wing leads and RoHS-compliant NiPdAu finish. Thermal resistance R_θJA is 87.9°C/W, supporting moderate-power continuous operation with standard PCB copper area.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ULQ2003AQDRQ1, ULQ2003ATDQ1 offers lower maximum junction temperature (105°C vs. 125°C) but identical drive strength and packaging; versus ULN2003A, it adds automotive qualification and enhanced ESD robustness at no pinout or layout change.

Availability

ULQ2003ATDQ1 is available at Aetrix Electronics and suitable for automotive body electronics, industrial relay control, and embedded lighting systems requiring stable component supply across long production lifecycles.

Supply support for ULQ2003ATDQ1 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 company specializing in analog, embedded processing, and automotive ICs, with leadership in high-reliability power and interface solutions.

The ULQ200xA-Q1 product line delivers AEC-Q100-qualified Darlington arrays optimized for automotive relay, motor, lamp, and display driver applications - emphasizing robustness, integration, and drop-in compatibility with legacy ULN2003 designs.

FAQ

What is the maximum continuous current per channel for ULQ2003ATDQ1?

The ULQ2003ATDQ1 supports 500mA continuous collector current per Darlington channel under recommended operating conditions. This rating assumes proper PCB thermal design and ambient temperature ≤105°C. Derating applies above 25°C ambient, with total power dissipation limited by R_θJA = 87.9°C/W in SOIC package. ULQ2003ATDQ1 must not exceed this limit to maintain reliability in automotive environments.

Does ULQ2003ATDQ1 require external flyback diodes when driving relays?

No, ULQ2003ATDQ1 does not require external flyback diodes when driving relays because it integrates common-cathode clamp diodes connected between each collector output and the COM pin. To use this feature, connect the COM pin to the positive supply rail of the relay coil. ULQ2003ATDQ1's internal diodes safely recirculate inductive kickback energy, eliminating external components and board space.

Can ULQ2003ATDQ1 be used with 3.3V microcontrollers?

Yes, ULQ2003ATDQ1 is compatible with 3.3V microcontrollers: its 2.7kΩ input base resistors allow sufficient base drive at VI(on) ≈ 2.7–3.0V (tested at IC = 200–300mA). Input current is ~1.0–1.35mA at 3.85V, well within GPIO sink capability. ULQ2003ATDQ1 thus interfaces directly with 3.3V logic without level-shifting or additional biasing circuitry.

What is the purpose of the E and COM pins on ULQ2003ATDQ1?

Pin 8 (E) is the common emitter - it serves as the shared ground return path for all seven Darlington channels and must be connected to system ground. Pin 9 (COM) is the common cathode node for internal clamp diodes - it must be connected to the positive supply rail of inductive loads (e.g., relay coil V_CC) to enable flyback current recirculation. ULQ2003ATDQ1 requires both connections for safe inductive switching.

Is ULQ2003ATDQ1 pin-compatible with ULN2003A?

Yes, ULQ2003ATDQ1 is pin-compatible with ULN2003A: both use identical 16-pin SOIC (D) package, matching pin functions (1B–7B, 1C–7C, E, COM), and share the same 2.7kΩ input resistor value. ULQ2003ATDQ1 replaces ULN2003A in automotive designs requiring AEC-Q100 qualification, higher ESD tolerance (±2000V HBM), and guaranteed −40°C to +105°C operation - with no PCB layout changes needed.