Texas Instruments ULN2002AN

Overview

ULN2002AN from Texas Instruments is a 7-channel high-voltage, high-current Darlington transistor array designed for interfacing low-voltage logic (14–25V PMOS-compatible inputs) with inductive loads. It delivers 500mA per channel, supports 50V collector-emitter voltage, integrates input Zener clamping and common-cathode flyback diodes, and is used in relay drivers, lamp control, and stepper motor interfaces.

For engineers reviewing the ULN2002AN datasheet, ULN2002AN pinout, ULN2002AN application, or ULN2002AN equivalent, this page provides verified electrical specs, validated package dimensions, confirmed thermal metrics for PDIP-16, real-world switching behavior (0.25–1μs propagation), and two functionally comparable alternatives with documented parameter differences.

Technical Context

The ULN2002AN implements seven independent NPN Darlington pairs, each with integrated series Zener diode and resistor at the input to limit current for 14–25V PMOS logic compatibility. Its open-collector outputs share a common emitter (pin 8) and a common-cathode clamp diode node (pin 9), enabling safe energy dissipation from inductive loads without external components.

It operates across –40°C to +70°C ambient temperature, features 50V absolute maximum collector-emitter voltage, and exhibits V_CE(sat) of 0.9–1.6V depending on drive current (100–350mA) and base input current (250–500μA). Input current is specified at 0.82–1.25mA when VI = 17V.

Key Specifications

Pinout & Package

ULN2002AN is housed in a 16-pin plastic dual in-line package (PDIP-16), measuring 19.30mm × 6.35mm, with through-hole mounting and industry-standard lead pitch (2.54mm).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ULN2002AN, ULN2003AN offers faster logic-level compatibility but no Zener input protection, while ULN2004AN reduces input power draw at higher voltages but sacrifices PMOS-specific clamping - all three share identical pinout, package, and output stage architecture.

Availability

ULN2002AN is available at Aetrix Electronics and suitable for relay control, lamp driving, and stepper motor phase switching requiring stable component supply across industrial automation, building management, and test equipment programs.

Supply support for ULN2002AN 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, embedded processing, and connectivity solutions for industrial, automotive, and communications markets.

The ULN200x family was developed to simplify high-voltage, high-current interfacing in industrial control systems - specifically addressing PMOS, TTL, and CMOS logic level translation with integrated protection and ruggedized output stages.

FAQ

What is the maximum continuous collector current per channel for ULN2002AN?

The ULN2002AN supports 500mA maximum collector current per Darlington channel under recommended operating conditions (TA ≤ 70°C, duty cycle considerations applied). This rating assumes proper PCB copper area and airflow; derating is required above 70°C ambient or at high duty cycles, as shown in Figure 5-4 of the datasheet. The ULN2002AN achieves this with V_CE(sat) of 1.2–1.6V at 350mA, directly impacting thermal design.

How does ULN2002AN differ from ULN2003AN in input interface design?

The ULN2002AN uses internal Zener diodes and series resistors to safely accept 14–25V PMOS logic inputs, whereas ULN2003AN employs a fixed 2.7kΩ base resistor optimized for 3.3V/5V TTL and CMOS. ULN2002AN's input structure prevents overcurrent damage when driven from higher-voltage logic, making it unsuitable as a direct replacement for ULN2003AN in low-voltage systems - and vice versa.

Can ULN2002AN drive inductive loads without external flyback diodes?

Yes - ULN2002AN includes seven integrated common-cathode clamp diodes connected between each collector output and the COM pin (pin 9). When COM is tied to the inductive load's positive supply rail, these diodes provide a path for flyback current, eliminating the need for external diodes. This is confirmed in the device description, pin function table, and functional block diagram (Figure 7-1).

What is the operating temperature range for ULN2002AN?

The ULN2002AN is rated for an operating free-air temperature range of –40°C to +70°C, as specified in Section 5.3 (Recommended Operating Conditions) of the TI datasheet SLRS027T. This range applies to the standard "ULN200xA" grade; extended-temperature variants (e.g., ULN2003AI) support up to +105°C but are not applicable to ULN2002AN.

Is ULN2002AN pin-compatible with other ULN200x devices in PDIP-16 package?

Yes - ULN2002AN, ULN2003AN, ULN2004AN, and ULQ2003AN share identical 16-pin PDIP mechanical footprint and pinout (as shown in Figure 4-1 and Table 4-1). All feature inputs on pins 1–7, outputs on pins 16–10, E on pin 8, and COM on pin 9. However, input circuitry differs significantly, so electrical compatibility must be verified per application.