ULN2803ADWR Darlington Transistor Array Advantages, Market Trends, Applications, Pinout and Feature Description
25 December 2023
Ⅱ. What are the advantages of the ULN2803ADWR chip?
Ⅲ. Market trends of ULN2803ADWR
Ⅳ. Where is ULN2803ADWR mainly used?
Ⅴ. Symbol, footprint and pin configuration of ULN2803ADWR
Ⅵ. Precautions for using ULN2803ADWR
Ⅶ. ULN2803ADWR feature description
The ULN2803ADWR chip is a Darlington transistor array chip produced by Texas Instruments. This chip is widely used in various control circuits that require high current and high voltage, such as LED lighting control, relay drive and stepper motor control. This article will introduce ULN2803ADWR in terms of advantages, market trends, uses, pinout, etc. After understanding its characteristics and application scenarios, I believe you will have a deeper understanding of this chip and can better apply it to actual projects.
The ULN2803ADWR device is a 50V, 500mA Darlington transistor array. The device consists of eight pairs of NPN Darlingtons with high voltage outputs and common cathode clamping diodes for switching inductive loads. The collector current rating of each Darlington pair is 500mA. Darlington pairs can be connected in parallel for higher current capabilities. It has applications in lamp drivers, relay drivers, display drivers, line drivers and logic buffers. Each Darlington pair of this ULN2803ADWR device has a 2.7-kΩ series base resistor for direct operation with TTL or 5V CMOS devices.
Replacements and equivalents:
Its advantages mainly include the following four points. First, it has wide applicability. The ULN2803ADWR chip can be used in a variety of application scenarios such as relay drivers, stepper motor drivers, LED displays, etc. Secondly, its output port is an ordinary GPIO interface, which is easy to connect to various microcontrollers and microcontrollers, and is flexible and convenient to use. In addition, it has excellent reliability and stability. It uses high-quality semiconductor materials and manufacturing processes to ensure stable operation in various harsh environments. The ULN2803ADWR chip has built-in overvoltage, overcurrent, and overheating protection circuits, which can automatically cut off the output under abnormal conditions to ensure the safety and stability of the system. Finally, it has a higher current output capability. The ULN2803ADWR chip has 8 outputs, each output can withstand a current of 500mA, and the total output current can reach 3.5A. Therefore, it can stably drive high-power loads and meet the needs of different application scenarios.
The graphs below show the price and inventory trends for ULN2803ADWR over the last three months, respectively.
1. Price trend (2023/09/24 - 2023/12/17)
Please note that what is shown in the figure is the market reference average price, in RMB. The price of ULN2803ADWR fluctuates between 10 and 15 yuan. This price change may be affected by various factors such as market demand and supply.
2. Inventory trend (2023/09/24 - 2023/12/17)
The stock level of ULN2803ADWR has remained within a relatively stable range with small fluctuations. At present, the stock level of this model is around 290k to 450k, providing sufficient supply guarantee for purchasers.
1. Industrial automation: Industrial automation systems require reliable control and drive circuits to automate and intelligently control production lines. ULN2803ADWR chips play a key role in industrial automation, used to control a variety of electrical and mechanical equipment.
2. Medical devices: In the medical field, it can be used to control and drive various devices such as syringes, medical imaging equipment and laboratory instruments. It provides reliable current amplification and drive functions, which help ensure the stability and performance of the equipment.
3. Solenoid valve control: Solenoid valves are commonly used in fluid control applications such as liquid delivery, misting systems and gas valves. the ULN2803ADWR chip can be used to provide drive current to accurately control the operation of solenoid valves, ensuring that they are opened and closed as required.
4. Relay drivers: The ULN2803ADWR chip can be used to control and drive relays. Relays typically require relatively high currents to trigger and hold, and this chip provides reliable driving capabilities, making them suitable for a variety of applications such as remote switches, security systems, and automation systems.
5. Stepper motor driver: The ULN2803ADWR chip can also be used to control stepper motors, providing the required current and voltage for precise position and speed control. This is more common in areas such as robotics, 3D printers and CNC machine tools.
6. LED displays: Large LED displays often require precise control to manage hundreds or even thousands of LEDs. ULN2803ADWR can be used to control arrays of LEDs to ensure that they operate at the correct brightness and mode.
The above figure shows the symbol, footprint and pin configuration of ULN2803ADWR respectively. It has 18 pins and comes in a SOIC-18 package. Its pin names are as follows.
Pin 1~8 (1B~8B): Channel 1 through 7 darlington base input
Pin 1~8 (1C~8C): Channel 1 through 7 darlington collector output
Pin 9 (GND): Common Emmitter shared by all channels (typically tied to ground)
Pin 10 (COM): Common cathode node for flyback diodes (required for inductive loads)
Summarized below are some guidelines that should be followed during use of the ULN2803ADWR.
• ULN2803ADWR cannot exceed the absolute maximum ratings shown in the data sheet. Once exceeded, it will cause permanent damage to the device.
• The pin layout of ULN2803ADWR is clear and easy to solder and install. But when welding, we should pay attention to controlling the welding temperature and time to avoid damaging the chip or affecting its performance.
• When the ULN2803ADWR chip is used as an inductive load driver, it is recommended to limit its chip junction temperature to below 125°C.
• When using ULN2803ADWR in coil driving applications, we need to determine the input voltage range, temperature range, output and drive current, and power consumption. The ULN2803ADWR has a collector current rating of 500mA per Darlington pair, for a total current capability of 4A. When selecting a connected load, make sure its operating current does not exceed the current limit of the chip to avoid burning the chip or causing other problems.
• The input signal of ULN2803ADWR needs to be active low level, that is, when the input signal is low level and reaches a certain threshold, the corresponding Darlington pair will be turned on. If the input signal is high level, it may cause the chip to not work properly.
Each channel of ULN2803ADWR consists of Darlington connected NPN transistors. This connection creates the effect of a single transistor with a very high current gain (β2). This can be as high as 10,000 AA at certain currents. The very high β allows for high output current drive with a very low input current, essentially equating tooperation with low GPIO voltages.
The GPIO voltage is converted to base current via the 2.7 kQ resistor connected between the input and base of the pre-driver Darlington NPN. The 7.2 kQ & 3.0 kQ resistors connected between the base and emitter of each respective NPN act as pul-downs and suppress the amount of leakage that may occur from the input. The diodes connected between the output and COM pin is used to suppress the kick-back voltage from an inductive load that is excited when the NPN drivers are turned off (stop sinking) and the stored energy in the coils causes a reverse current to flow into the coil supply via the kick-back diode.
ln normal operation the diodes on base and collector pins to emitter will be reversed biased. lf these diodes are forward biased, internal parasitic NPN transistors will draw (a nearly equal) current from other (nearby) device pins.
Frequently Asked Questions
1. What is the operating temperature range of ULN2803ADWR?
The operating temperature of ULN2803ADWR ranges from -40°C to 85 °C.
2. What is the ULN2803ADWR used for?
The ULN2803ADWR is used as a driver for high-current loads such as relays, motors, and solenoids in various electronic applications.
3. What is the replacement and equivalent of ULN2803ADWR?
You can replace the ULN2803ADWR with the ULN2003ADR, ULN2003D1013TR, ULN2803ADW, ULN2803ADWG4 or ULN2803ADWRG4.
4. How is the ULN2803ADWR typically controlled?
The ULN2803ADWR is typically controlled by a microcontroller or other digital logic circuitry. It has input pins for each channel, and when a high signal is applied to a specific input, the corresponding output channel is activated.
