Texas Instruments ULN2003AIDRG4

Overview

ULN2003AIDRG4 from Texas Instruments is a 7-channel high-voltage, high-current NPN Darlington transistor array designed for logic-level interfacing to inductive and resistive loads. It features 500mA per channel collector current rating, 50V output voltage capability, integrated common-cathode clamp diodes, 2.7kΩ input base resistors for direct TTL/5V CMOS compatibility, and operates across –40°C to 70°C ambient temperature - widely used in relay and stepper motor control circuits.

For engineers reviewing the ULN2003AIDRG4 datasheet, ULN2003AIDRG4 pinout, ULN2003AIDRG4 application, or ULN2003AIDRG4 equivalent, key selection criteria include verified sink-current capability under thermal constraints, COM pin configuration for inductive kickback suppression, input logic threshold behavior at 3.3V/5V, and SOIC-16 package thermal resistance (R_θJA = 88.6°C/W) for board-level power dissipation planning.

Technical Context

The ULN2003AIDRG4 integrates seven independent Darlington pairs with monolithic 2.7kΩ series base resistors, enabling direct drive from standard 5V TTL or CMOS logic without external biasing. Each channel provides open-collector outputs with internal flyback diodes tied to a shared COM terminal, supporting safe switching of relays, solenoids, and lamps.

Its functional architecture relies on cascaded NPN transistors delivering β² current gain (~10,000 A/A), allowing ~0.35–0.5mA input current at 5V to switch up to 350mA load current while maintaining V_CE(sat) ≤ 1.6V. The device requires no external power supply beyond V_CC applied to COM for inductive loads.

Key Specifications

Pinout & Package

ULN2003AIDRG4 is housed in a 16-pin SOIC (Small Outline Integrated Circuit) package measuring 9.90mm × 3.91mm, with standard 1.27mm pitch and gull-wing leads suitable for automated PCB assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ULN2003ADR, ULN2003AIDRG4 offers identical performance with TI's specified matte tin (G4) finish, while ST's ULN2003D1013TR requires ≥6V input drive - making ULN2003AIDRG4 the optimal choice for direct 3.3V/5V microcontroller interfacing in relay and motor control.

Availability

ULN2003AIDRG4 is available at Aetrix Electronics and suitable for relay control, stepper motor actuation, and industrial lamp driving requiring stable component supply, long-lifecycle support, and guaranteed traceable sourcing.

Supply support for ULN2003AIDRG4 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 delivering analog and embedded processing solutions, with decades of expertise in interface ICs and industrial-grade power drivers.

The ULN200x family was engineered specifically for robust logic-to-load interfacing in industrial automation, appliance control, and electromechanical systems - prioritizing reliability, integrated protection, and ease of use over high-speed or precision analog performance.

FAQ

What is the maximum continuous current per channel for ULN2003AIDRG4?

The ULN2003AIDRG4 supports 500mA DC collector current per channel under recommended operating conditions. This rating assumes proper PCB copper area, ambient temperature ≤70°C, and adherence to derating curves in Figure 5-4 of the datasheet. At 200mA per channel with 7 channels active, total power dissipation remains within thermal limits for SOIC-16 packaging.

Does ULN2003AIDRG4 require external flyback diodes when driving relays?

No - ULN2003AIDRG4 includes integrated common-cathode clamp diodes connected from each collector to the COM pin. When COM is tied to the relay coil supply voltage, these diodes provide complete flyback protection. External diodes are unnecessary unless the load voltage exceeds 50V or non-standard diode recovery behavior is required.

Can ULN2003AIDRG4 be used with 3.3V microcontrollers?

Yes - ULN2003AIDRG4's 2.7kΩ internal input resistors allow reliable turn-on with 3.3V logic. At 3.3V input, typical input current is ~1.2mA, sufficient to saturate the Darlington pair for loads up to 300mA. Verified operation is documented in Section 5.6 of the TI datasheet for ULN2003A devices.

What is the purpose of the E pin (Pin 8) on ULN2003AIDRG4?

Pin 8 (E) is the common emitter terminal for all seven Darlington pairs. It must be connected to system ground to complete the current path. Unlike the COM pin, E is not optional - leaving it unconnected prevents any channel from conducting. It is electrically isolated from COM and serves solely as the emitter reference node.

How does thermal performance differ between ULN2003AIDRG4 and ULN2003AD?

ULN2003AIDRG4 and ULN2003AD share identical SOIC-16 packaging and thermal metrics: R_θJA = 88.6°C/W, R_θJC = 50.1°C/W. The 'G4' suffix denotes TI's matte tin lead finish, which has no impact on thermal resistance. Both parts exhibit identical junction temperature rise under identical load and PCB conditions.