Overview
The ULN2801A is a high-current Darlington array produced by STMicroelectronics. It is part of a family of devices that include the ULN2802A, ULN2803A, and ULN2804A, each designed to interface with different standard logic families. The ULN2801A is specifically tailored for general-purpose applications and features a current limit resistor. This device contains eight Darlington transistors with common emitters and integral suppression diodes, making it suitable for driving inductive loads. Each Darlington transistor can handle a peak load current of 600 mA (500 mA continuous) and can withstand up to 50 V in the OFF state. The outputs can be paralleled to achieve higher current capabilities, and the input-opposite-output pinout simplifies board layout.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Output Voltage (VO) | 50 | V |
| Continuous Collector Current (IC) | 500 | mA |
| Continuous Base Current (IB) | 25 | mA |
| Power Dissipation (one Darlington pair) | 1 | W |
| Power Dissipation (total package) | 2.25 | W |
| Operating Ambient Temperature Range (TA) | -20 to 85 | °C |
| Storage Temperature Range (TSTG) | -55 to 150 | °C |
| Junction Temperature (TJ) | -20 to 150 | °C |
| Thermal Resistance Junction-Ambient (RthJA) | 55 | °C/W |
Key Features
- Eight Darlington transistors with common emitters
- Output current up to 500 mA (600 mA peak)
- Output voltage up to 50 V
- Integral suppression diodes for inductive loads
- Versions for all popular logic families (ULN2801A, ULN2802A, ULN2803A, ULN2804A)
- Outputs can be paralleled for higher current capability
- Inputs pinned opposite outputs to simplify board layout
- Supplied in an 18-lead plastic DIP with a copper lead form
Applications
The ULN2801A is versatile and can be used in a variety of applications, including:
- Driving inductive loads such as relays, solenoids, and DC motors
- Interface between low-level logic circuits and high-current loads
- Power switching and amplification in industrial and consumer electronics
- Automotive and aerospace applications where high reliability is required
Q & A
- What is the maximum output current of the ULN2801A?
The maximum continuous output current is 500 mA, with a peak current rating of 600 mA.
- What is the maximum output voltage the ULN2801A can handle?
The ULN2801A can withstand up to 50 V in the OFF state.
- What types of logic families can the ULN2801A interface with?
The ULN2801A is designed for general-purpose applications, but other versions (ULN2802A, ULN2803A, ULN2804A) are available for interfacing with 14-25 V PMOS, 5 V TTL and CMOS, and 6-15 V CMOS.
- Can the outputs of the ULN2801A be paralleled?
- What is the package type of the ULN2801A?
The ULN2801A is supplied in an 18-lead plastic DIP with a copper lead form.
- What is the operating temperature range of the ULN2801A?
The operating ambient temperature range is -20 to 85 °C.
- Does the ULN2801A have built-in suppression diodes?
- How does the pinout of the ULN2801A simplify board layout?
The inputs are pinned opposite the outputs, which simplifies board layout.
- What is the thermal resistance junction-ambient (RthJA) of the ULN2801A?
The thermal resistance junction-ambient (RthJA) is 55 °C/W.
- Is the ULN2801A RoHS compliant?
