STMicroelectronics ULN2804A

The STMicroelectronics ULN2804A is a high-voltage, high-current Darlington transistor array. It consists of four pairs of Darlingtons with a common emitter and is designed to drive loads such as relays, solenoids, and LED displays. It can handle high voltages and currents, making it suitable for various interface and control circuits. Functions - Darlington Pair Arrangements: It contains four separate Darlington pairs which provide high current gain. - Inductive Load Driving: The device is equipped with flyback diodes for driving inductive loads safely. - High Voltage and Current Handling: Capable of switching high voltages (up to 50V) and currents (up to 500mA). - Common Emitter Configuration: It has a common emitter output, simplifying design and integration. Applications - Relay Drives: Suitable for driving electromagnetic relays in various electronic systems. - Solenoid Control: Widely used in applications requiring the operation of solenoid-driven mechanisms. - LED Displays: Commonly used in multiplexed LED display drivers. - Industrial Control Systems: Employed in automation and control systems where high current driving capability is needed. - Motor Control: Can be used for driving small DC motors in various electronic applications. Alternative Parts - ULN2003A: Similar device but with less current handling capability and fewer outputs (7 outputs). - ULN2004A: Provides eight Darlington pairs and is suited for different applications requiring a larger number of outputs. - ULN2803A: An 8-channel Darlington driver ideally suited for driving larger loads. - MPSU01/MPSU05: There are discrete alternatives if only a few channels are needed rather than a full array. Embedded Modules - An embedded module with the ULN2804A can be found in development boards designed for automation and control. - Integrated shields for Arduino or Raspberry Pi that facilitate high-power driving capabilities. - Custom PCBs utilizing the ULN2804A for specific applications in robotics or industrial automation. Related Q&A Q1: What is the maximum voltage and current that the ULN2804A can handle? A1: The ULN2804A can handle a maximum voltage of 50V and a maximum current of 500mA per channel. Q2: Can the ULN2804A drive inductive loads directly? A2: Yes, the ULN2804A has built-in flyback diodes which allow it to safely drive inductive loads such as relays and solenoids. Q3: How many channels does the ULN2804A contain? A3: The ULN2804A contains four channels, allowing you to control four separate loads or devices. Q4: What is the typical gain of the Darlingtons within the ULN2804A? A4: The ULN2804A exhibits a high current gain, typically around 1000 or more, depending on the operating conditions. Q5: What are the recommended applications for the ULN2804A? A5: Recommended applications include relay driving, solenoid control, LED display driving, industrial control systems, and motor control applications.