Part Number: ULN2002AN

Manufacturer: Texas Instruments

Description: TRANS 7NPN DARL 50V 0.5A 16DIP

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Technical Specifications of ULN2002AN

Datasheet  ULN2002AN datasheet
Category Discrete Semiconductor Products
Family Transistors – Bipolar (BJT) – Arrays
Manufacturer Texas Instruments
Packaging Tube
Transistor Type 7 NPN Darlington
Current – Collector (Ic) (Max) 500mA
Voltage – Collector Emitter Breakdown (Max) 50V
Vce Saturation (Max) @ Ib, Ic 1.6V @ 500μA, 350mA
Current – Collector Cutoff (Max)
DC Current Gain (hFE) (Min) @ Ic, Vce
Power – Max
Frequency – Transition
Mounting Type Through Hole
Package / Case 16-DIP (0.300″, 7.62mm)
Supplier Device Package 16-PDIP

ULN2002AN Description

The ULx200xA components are arrays of Darlington transistors operating at high voltages and enormous currents. They are each composed of seven NPN Darlington pairs, and thanks to their common-cathode clamp diodes, they can switch inductive loads at high voltage.

A single Darlington pair can provide up to 500 mA of collector current. The Darlington pairs could be linked in parallel to increase the available current. These components have many applications, including logic buffers, line drivers, lamp drivers, relay drivers, hammer drivers, display drivers (for LED and gas discharge), and displays. For 100-V (otherwise interchangeable) versions of the ULx2003A devices, consult the SLRS023 data sheet for the SN75468 and SN75469 devices.

The ULN2002A is designed to work best with PMOS devices that use voltages between 14 and 25 volts. A Zener diode and a resistor are linked in series at each input to restrict how much current can enter the device. The ULx2003A devices’ Darlington pairs each have a 2.7 k series base resistor, enabling them to communicate directly with TTL or 5-V CMOS devices.

The 10.5-k series base resistor of the ULx2004A devices enables direct operation from CMOS devices demanding supply voltages of 6 V to 15 V. The input current and voltage requirements of the ULx2004A device are, respectively, lower than those of the ULx2003A and ULn2002A devices.


  • Collector Current Rated at 500 mA (Single Output).
  • Outputs with a high voltage: 50 V. Output clamp diodes.
  • Inputs that work with different kinds of logic.

Relay-Driver Applications

Detailed Description

This common tool has been used well in many different situations, showing its usefulness and flexibility. This is because the device has 7 transistors built in, and each one can work over a wide range of GPIOs and sink up to 500 mA. Seven high-voltage, high-current NPN Darlington transistors comprise the ULN2003A chip. Each component’s collector and emitter terminals are both open.

These devices have suppression diodes built in for inductive loads for maximum effectiveness. The ULN2003A can work directly with TTL or CMOS at 5 V or 3.3 V supply voltages with a base resistor connected to each Darlington pair in series. The ULN2003A device can solve many interface problems, including those with solenoids, relays, lamps, small motors, and LEDs. Paralleling the outputs can help with applications that need larger sink currents than a single output can provide. This thing can handle temperatures from -40°C to 105°C.

Feature Description

The ULN2003A uses a Darlington arrangement of NPN transistors for each channel. This setup makes it look like a single transistor (2) with a very high current gain is installed. This can go up to tens of thousands of A/A in certain situations. Small GPIO voltages are enough to send large currents to the output because the values are so high. The 2.7-k resistor between the input and base of the predriver Darlington NPN turns the GPIO voltage into the base current. Each NPN has a 7.2 k or 3 k pulldown resistor connected between its base and emitter to stop input leakage. When the NPN drivers are turned off (when they stop sinking), a diode is put between the output and COM pin to stop the kick-back voltage from the inductive load from flowing back into the coil supply. During normal operation, diodes connected to the emitter from the base and collector pins will be forward-biased. When these diodes are forward-biased, they use current from nearby device pins to power the internal parasitic NPN transistors.

The ways the device works to power inductive objects When the COM pin is connected to the coil supply voltage, the ULN2003A device can drive inductive loads because it has built-in diodes that stop power from bouncing back.

Resistive Load Drive

The ULN2003A device needs a pull-up resistor to sink current and reach a logic high level while driving a resistive load. It is allowed to leave the COM pin disconnected in some circumstances.

Application Information

The ULN2003A device is typically driven by an MCU or logic device rather than one that can handle high voltage or current. The ULN2003A device is widely utilized for driving inductive loads in this setup. This category includes mechanical parts like motors, solenoids, and relays.

Power Supply Recommendations

This device doesn’t require a power supply. However, the COM pin is typically wired to the power source. The output voltage in this situation mustn’t go noticeably above the voltage on the COM pin. This difference significantly biases the fly-back diodes, causing a high current to flow into COM and potentially overheating the device or possibly melting the on-chip metal.


● Layout Guidelines

Thin traces can be utilized on the input of ULN2003A devices because low-current circuitry is frequently used to operate them. As much as you can, keep the input channels apart to avoid interference. TI advises utilizing strong cables capable of generating the necessary high currents for the output. The required wire thickness will depend on the trace material’s desired driving current and current density. Wide trace width is preferred because the channel’s currents return to one emitter. In some circumstances, up to 2.5 A may be required.


To sum up, the ULN2002AN is a key part of low-power microcontrollers that are used to control high-power devices. The seven Darlington transistor arrays on the IC allow it to switch quickly and reliably in various applications, such as motors, cars, and industrial control. Users can make the most of the ULN2002AN’s features and functions if they know its pinout, its features, and how it works.

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