ULN2801A Darlington Transistors by STMicroelectronics – High-Voltage, High-Current Driver Array
The Darlington Transistors ULN2801A by STMicroelectronics are a high-performance solution for driving inductive loads such as relays, solenoids, and lamps. This 8-channel Darlington driver array provides high-voltage, high-current capabilities with TTL/CMOS compatibility, making it ideal for interfacing logic circuits with power components in a range of industrial and consumer electronics.
In this blog, we’ll review the technical specs, features, application areas, wiring guide, and real-world use case that highlights the power and flexibility of these Darlington Transistors.
Technical Specifications of ULN2801A
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Manufacturer: STMicroelectronics
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Part Number: ULN2801A
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Type: Darlington Transistors
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Number of Channels: 8
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Output Voltage: Up to 50V
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Output Current per Channel: 500mA
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Input Compatibility: TTL/CMOS
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Clamp Diodes: Integrated for inductive load protection
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Package: DIP-18
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Category: Semiconductors, Discrete Semiconductors, Transistors, Darlington Transistors
The ULN2801A is an excellent power interface for digital systems where compact design and reliability are required.
Key Features of ULN2801A Darlington Transistors
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Eight Darlington Channels for parallel or independent use
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High Output Voltage (50V) and Current Drive (500mA/channel)
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TTL/CMOS Input Compatibility – Easy logic interfacing
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Built-in Clamp Diodes – For safe inductive switching
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Robust DIP-18 Package – Easy to integrate in standard PCBs
These features make ULN2801A Darlington Transistors a go-to choice in many semiconductor applications.
Applications of ULN2801A
The ULN2801A Darlington Transistors are perfect for:
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Relay and Solenoid Drivers
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Stepper Motor Controls
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LED and Lamp Drivers
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Printer Heads
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Display Systems
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Industrial Automation Interfaces
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Consumer Electronics with TTL Logic
These transistors provide essential interfacing between low-voltage logic and high-current loads, making them crucial components in many discrete semiconductor designs.
Wiring and Connection Overview
Pinout Details (DIP-18):
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Pins 1–8: Inputs from TTL/CMOS
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Pins 11–18: Outputs to load
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Pin 9: Common ground
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Pin 10: Common freewheeling diode (connect to load supply)
The wiring is straightforward and reliable, ensuring minimal heat generation and consistent switching behavior across all eight Darlington Transistors.
Use Case Scenario: Relay Control in HVAC Systems
Problem: A commercial HVAC system required a reliable, compact solution to control eight relays via a microcontroller.
Solution: The engineering team implemented the ULN2801A Darlington Transistors from STMicroelectronics, allowing the microcontroller to control all relays with a single IC.
Result: Reduced PCB footprint, simplified wiring, and reliable relay activation with built-in protection — all using one cost-effective semiconductor device.
Download Datasheet for ULN2801A
Need pin configuration, timing charts, and electrical characteristics?
[Download the ULN2801A Datasheet from Xon Electronics]
Why Buy from Xon Electronics?
When you buy ULN2801A Darlington Transistors from Xon Electronics, you get:
- 100% Genuine STMicroelectronics Parts
- Worldwide Shipping to USA, India, Australia, Europe & More
- Special Pricing for Bulk Orders
- Easy Access to Technical Datasheets
- Safe and Secure Online Transactions
Trust Xon Electronics for all your Semiconductors, Discrete Semiconductors, and Darlington Transistors.
FAQs – ULN2801A Darlington Transistors
Q1. Can ULN2801A drive inductive loads like relays and motors?
Yes, it's specifically designed for such loads with built-in clamp diodes.
Q2. What logic level is supported at the input?
It supports both TTL and CMOS logic inputs.
Q3. How much current can each output handle?
Each output channel can sink up to 500mA.
Q4. Is the device RoHS compliant?
Yes, it is fully compliant with environmental standards.
Q5. Do you ship internationally?
Yes, we ship to the USA, India, Australia, Europe, and many other countries.
Conclusion
The ULN2801A Darlington Transistors by STMicroelectronics are reliable, efficient, and compact solutions for driving inductive or high-current loads from low-power logic devices. Their integration of clamp diodes and TTL/CMOS compatibility makes them an excellent choice for embedded and industrial applications alike.
Now available at Xon Electronics — with global shipping to USA, India, Australia, Europe, and more!