ULN2803 ULN2803AG SOP-18

The ULN2803 and ULN2803AG are integrated circuits (ICs) known as Darlington transistor arrays. This technical exploration delves into their functionalities, technical specifications, and common applications to empower you to determine if they are the ideal choice for interfacing low-power microcontrollers with higher-power devices in your electronic projects.

Both the ULN2803 and ULN2803AG are essentially identical, with the “AG” suffix potentially indicating a variation in package marking or lead finish (refer to datasheet for confirmation). These ICs integrate eight individual Darlington transistor pairs within a single SOP-18 (Small Outline Package) package. Each Darlington pair acts as an amplifier, allowing a low-current control signal from a microcontroller to regulate a larger current for driving various external devices.

Key Features of ULN2803 ULN2803AG SOP-18:

• • Eight Darlington Transistor Pairs: Provides the ability to control eight independent high-current loads using low-current microcontroller outputs.
  • High-Voltage Outputs: Output voltage ratings typically around 50V (verify datasheet), enabling control of various higher-voltage devices.
  • High-Current Outputs: Each Darlington pair can handle moderate output currents (typically in the range of 500mA, verify datasheet), suitable for driving relays, LEDs, small motors, and other loads.
  • Input-Output Isolation: Provides optical isolation between the low-voltage control signals and the high-voltage/current outputs, enhancing safety and reducing noise interference. (Note: Not all versions offer true optical isolation, verify datasheet).

Technical Specifications of ULN2803 ULN2803AG SOP-18:

• • Supply Voltage (Vcc): The voltage range the IC can operate within (typically around 5V).
  • Input Voltage (Vin): The valid voltage range for the control input signals (usually compatible with microcontroller logic levels).
  • Output Voltage (Vout): The voltage range the outputs can handle (typically up to 50V, verify datasheet).
  • Output Current (Iout): The maximum current each output pair can handle (typically around 500mA, verify datasheet).
  • Current Gain (hFE): The current amplification factor of the Darlington pairs (refer to datasheet for specific value).

Applications of ULN2803 ULN2803AG SOP-18:

• • Driving Relays: Enables microcontrollers to control relays that switch on/off higher-power circuits.
  • LED Driver Circuits: Can be used to drive multiple LEDs or LED strips with higher current requirements.
  • Interfacing with Stepper Motors: Can be used in conjunction with driver ICs to control stepper motors.
  • Solenoid Control: Provides a way for microcontrollers to control solenoids with moderate current requirements.

Equivalents of ULN2803 ULN2803AG SOP-18:

• • Several functional equivalents of the ULN2803/ULN2803AG exist, offering similar functionalities with potential variations in output current ratings, package types, or voltage specifications. Some examples include the ULN2003, ULN2804, and MJD2955.
  • ULN2803/ULN2803AG
  • Darlington Transistor Array
  • High-Current Driver IC
  • Relay Driver
  • Microcontroller Interface IC

Package Includes:

• • 1 x ULN2803 ULN2803AG SOP-18