Texas Instruments ULN2004ANSR

Overview

ULN2004ANSR from Texas Instruments is a 7-channel high-voltage, high-current Darlington transistor array designed for interfacing low-voltage logic (6V–15V CMOS) with inductive loads. It delivers 500mA per channel, supports 50V collector-emitter voltage, integrates common-cathode clamp diodes, and uses 10.5kΩ input base resistors for direct CMOS compatibility - widely deployed in relay and stepper motor control circuits.

For engineers reviewing the ULN2004ANSR datasheet, ULN2004ANSR pinout, ULN2004ANSR application, or ULN2004ANSR equivalent, key selection criteria include per-channel current capability, integrated flyback diode configuration, input resistor value for logic-level compatibility, thermal derating at elevated ambient temperatures, and package-specific R_θJA (95.0°C/W for SOP-16).

Technical Context

The ULN2004ANSR implements seven independent NPN Darlington pairs, each with a dedicated 10.5kΩ series input resistor enabling direct drive from 6V–15V CMOS logic without external biasing. Its internal common-cathode clamp diodes are connected to the COM pin and required for safe switching of inductive loads such as relays and solenoids.

It operates with a maximum collector-emitter voltage of 50V, supports continuous per-channel sink current up to 500mA (derated per duty cycle and ambient temperature), and exhibits V_CE(sat) ≤1.6V at I_C = 350mA and I_I = 500μA - critical for minimizing power loss in high-current switching applications.

Key Specifications

Pinout & Package

SOP-16 package (10.30mm × 5.30mm), surface-mount, gull-wing leads; RoHS-compliant, moisture sensitivity level (MSL) 3.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ULN2003ADR and ULQ2004A, the ULN2004ANSR provides optimal balance of CMOS voltage compatibility (6V–15V), thermal performance (70°C max ambient), and cost-efficiency for mainstream industrial control - avoiding unnecessary over-specification while ensuring robust interface margin.

Availability

ULN2004ANSR is available at Aetrix Electronics and suitable for relay drivers, stepper motor controllers, and industrial lamp/LED drivers requiring stable component supply across production lifecycles.

Supply support for ULN2004ANSR 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 for industrial, automotive, and personal electronics markets.

The ULN200x family was engineered to simplify high-current logic interfacing - specifically targeting cost-sensitive, space-constrained applications where reliability under inductive switching stress is essential.

FAQ

What is the maximum continuous current per channel for ULN2004ANSR?

The ULN2004ANSR supports 500mA continuous collector current per Darlington channel under specified thermal conditions. This rating assumes proper PCB copper area, ambient temperature ≤70°C, and adherence to duty-cycle derating curves - e.g., maximum current drops to ~350mA at 100% duty cycle in SOP-16 package due to thermal limits. Always verify power dissipation using V_CE(sat) and actual load current in your design.

Can ULN2004ANSR drive 24V relays directly?

Yes, ULN2004ANSR can directly drive 24V relays. Its 50V collector-emitter voltage rating and integrated clamp diodes (when COM is connected to the 24V rail) provide complete inductive load protection. Ensure the relay coil current remains ≤500mA and that the E pin is grounded. No external flyback diodes or base resistors are needed - the 10.5kΩ internal resistors make it compatible with 6V–15V CMOS control signals.

How does ULN2004ANSR differ from ULN2003A in terms of input compatibility?

The ULN2004ANSR uses a 10.5kΩ input base resistor, enabling reliable operation from 6V–15V CMOS logic with input current ≤1.45mA at 15V. In contrast, ULN2003A uses a 2.7kΩ resistor, drawing ≥0.5mA at 5V but risking excessive input current or logic overdrive above 6V. ULN2004ANSR is therefore preferred for higher-voltage CMOS interfaces, while ULN2003A suits 3.3V/5V TTL/CMOS systems.

Is a pull-up resistor required on the output side of ULN2004ANSR?

No, a pull-up resistor is not required on the output side of ULN2004ANSR when driving inductive loads - the COM pin connects to the load's positive supply, and the Darlington sinks current through the coil to ground. For resistive loads (e.g., LEDs), a pull-up to V_CC is necessary to establish a logic-high level when the output is off; in those cases, the ULN2004ANSR acts as an open-collector inverter stage.

What is the purpose of the COM pin on ULN2004ANSR?

The COM pin on ULN2004ANSR is the common cathode node for all seven internal clamp diodes. It must be connected to the positive supply voltage of the inductive load (e.g., relay coil or motor winding) to provide a recirculation path for back-EMF energy when the Darlington turns off. Leaving COM unconnected or grounding it disables flyback protection and risks device damage during inductive switching.