STMicroelectronics ULQ2001A

Overview

ULQ2001A from STMicroelectronics is a 7-channel Darlington transistor array in DIP-16 package, designed for high-voltage (50 V), high-current (500 mA per channel) switching of inductive loads. It integrates suppression diodes, supports TTL/CMOS/PMOS/DTL logic inputs, and operates across -40 to 105 °C - widely used in relay drivers, solenoid controls, and LED display multiplexing.

For engineers reviewing the ULQ2001A datasheet, ULQ2001A pinout, ULQ2001A application, or ULQ2001A equivalent, key selection criteria include output voltage rating (50 V), continuous current per driver (500 mA), integrated clamp diode functionality, input compatibility with legacy logic families, and thermal resistance (70 °C/W, DIP-16).

Technical Context

The ULQ2001A implements seven independent open-collector NPN Darlington pairs with common emitters, each featuring an integrated flyback diode for inductive load protection. Its input pins are arranged opposite outputs to minimize PCB trace crossovers and reduce layout complexity.

It delivers guaranteed DC current gain (h_FE) ≥1000 at I_C = 350 mA and V_CE = 2 V, with V_CE(SAT) ≤1.6 V at 350 mA drive, enabling efficient low-side switching in industrial control modules and automotive body electronics where AEC-Q100 qualification is not required.

Key Specifications

Pinout & Package

ULQ2001A uses a 16-pin plastic DIP package (0.3-inch width) with copper lead-frame for reduced thermal resistance. Pin numbering follows standard dual-in-line convention, with inputs on one side and outputs on the opposite side to simplify routing.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ULN2003A and TD62003APG, ULQ2001A uniquely combines extended temperature operation (-40 to 105 °C), mirrored pinout for simplified layout, and 500 mA per channel capability - making it optimal for ruggedized industrial control boards where thermal margin and routing efficiency are critical.

Availability

ULQ2001A is available at Aetrix Electronics and suitable for industrial relay control, LED display multiplexing, thermal print-head interfacing, and solenoid actuation requiring stable component supply and long-term manufacturability.

Supply support for ULQ2001A 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, specializing in automotive, industrial, and power management ICs with strong analog and discrete product portfolios.

The ULQ2001A belongs to ST's high-voltage Darlington array product line, engineered specifically for robust, low-cost switching of inductive and resistive loads in harsh industrial environments where reliability and integration are prioritized over ultra-high speed.

FAQ

What is the maximum safe operating current per channel for continuous duty?

The ULQ2001A is rated for 500 mA continuous collector current per channel at T_A ≤ 105 °C with R_thJA = 70 °C/W. At 25 °C ambient, derating allows up to ~700 mA briefly, but sustained operation above 500 mA risks exceeding the 150 °C junction limit unless heatsinking is added.

Can multiple outputs be paralleled to increase current capacity?

Yes - the datasheet explicitly states outputs can be paralleled for higher current. When two channels are paralleled, total current capacity increases to 1 A, provided trace width and thermal design accommodate doubled power dissipation and both channels share current evenly via matched layout and identical load paths.

Is a current-limiting resistor required on the input pins?

No external resistor is mandatory because the ULQ2001A has built-in base resistors. Input current is self-limited: e.g., at V_IN = 5 V, II(ON) is ~1.35 mA for ULQ2003A-compatible logic - well within safe drive capability of most MCUs and logic gates without additional series resistance.

How should the COM pin be connected for inductive load operation?

The COM pin must be connected to the positive supply rail of the inductive load (e.g., +24 V). This ties the anodes of all internal clamp diodes to that rail, allowing stored magnetic energy to recirculate through the diode and load during turn-off - preventing voltage spikes that could damage the Darlington transistors or upstream circuitry.