STMicroelectronics ULQ2003A

Overview

ULQ2003A from STMicroelectronics is a 7-channel high-voltage, high-current Darlington array in DIP-16 package, designed for driving inductive loads such as relays and solenoids. Each channel delivers 500 mA continuous output current (600 mA peak), withstands 50 V output voltage, and integrates suppression diodes. It operates across -40 °C to 105 °C and accepts TTL/CMOS-compatible 5 V logic inputs.

For engineers reviewing the ULQ2003A datasheet, ULQ2003A pinout, ULQ2003A application, or ULQ2003A equivalent, this device is selected for robust load switching in automotive control modules, industrial PLC outputs, and relay driver stages where integrated flyback protection and thermal reliability are critical.

Technical Context

The ULQ2003A implements seven independent open-collector NPN Darlington pairs with common emitters and monolithically integrated clamp diodes across all outputs. Its input structure is optimized for 5 V TTL/CMOS logic compatibility, with VI(ON) threshold of 2.4–3.0 V at IC = 200–300 mA.

Each Darlington stage provides DC current gain (hFE) ≥1000 at IC = 350 mA and VCE = 2 V, while maintaining VCE(SAT) ≤1.6 V at IB = 500 µA and IC = 350 mA. Thermal resistance RthJA is 70 °C/W in DIP-16, enabling sustained 500 mA operation without forced cooling under ambient conditions.

Key Specifications

Pinout & Package

ULQ2003A is supplied in a 16-pin plastic dual in-line package (DIP-16) with copper lead-frame for reduced thermal resistance. Pin layout follows input-output opposition: inputs on one side (pins 1–7), outputs on opposite side (pins 11–17), with common emitter (pin 8) and ground (pin 16).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ULN2003A, ULQ2003A adds extended temperature range and automotive qualification; compared with TBD62083AFG, it trades off voltage headroom and lower VCE(SAT) for integrated protection and simpler layout - making it optimal for 12–24 V inductive load switching where reliability and integration are prioritized.

Availability

ULQ2003A is available at Aetrix Electronics and suitable for automotive body control modules, industrial PLC output stages, and thermal print head driver circuits requiring stable component supply and long-term manufacturability.

Supply support for ULQ2003A 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, digital, and mixed-signal ICs for automotive, industrial, and consumer markets.

The ULQ2003A belongs to ST's high-reliability Darlington array product line, engineered specifically for ruggedized load switching in harsh environments - emphasizing integrated protection, extended temperature operation, and automotive qualification readiness.

FAQ

What is the maximum safe continuous current per channel on ULQ2003A?

The ULQ2003A is rated for 500 mA continuous collector current per channel at TA ≤ 105 °C with proper PCB copper area (≥1 cm² per output pad). Derating is required above 70 °C ambient; at 105 °C, full 500 mA is supported only with RthJA ≤70 °C/W achieved via DIP-16 copper lead-frame and adequate board thermal relief.

Can ULQ2003A outputs be paralleled, and what is the resulting current capacity?

Yes - outputs can be paralleled to increase current capacity. With two outputs paralleled, total continuous current reaches 1 A (2 × 500 mA), provided traces and pads are sized accordingly and VCE(SAT) mismatch remains within ±0.1 V. Peak current scales to 1.2 A (2 × 600 mA), but thermal coupling must be managed to avoid localized overheating.

Does ULQ2003A require external flyback diodes when driving relays?

No - ULQ2003A includes monolithic clamp diodes across all seven outputs, connected from each collector to the common emitter (pin 8). These diodes provide complete flyback energy recirculation during inductive load turn-off, eliminating the need for external diodes in standard 12–24 V relay applications.

How does ULQ2003A differ from ULN2003A in terms of automotive suitability?

ULQ2003A is explicitly qualified to AEC-Q100 Grade 1 (−40 °C to 125 °C junction) and undergoes PAT, SYL, and SBL statistical testing; ULN2003A is commercial-grade only (−20 °C to 70 °C), lacks automotive qualification documentation, and is not recommended for automotive use per ST's official guidance.