The L7805 is a widely utilized voltage regulator within the L78xx series, known for its robustness and reliability in delivering a stable 5-volt output. As a three-terminal positive voltage regulator, it plays a crucial role in various electronic applications by providing a consistent voltage supply and ensuring circuit stability. The L7805 is available in multiple packages such as TO-220, TO-220FP, TO3, D²PAK, and DPAK, making it versatile for integration into different circuit designs. Its features, including internal current limiting, thermal shutdown, and safe area protection, contribute to its durability and performance in diverse operating conditions.


L7805 Overview

The L7805 is a robust member of the L78xx series of three-terminal positive voltage regulators, designed to provide a stable 5-volt DC output. Available in several packages including TO-220, TO-220FP, TO3, D²PAK, and DPAK, it supports a wide range of applications by offering fixed output voltages. These regulators are particularly effective for local on-card voltage regulation, mitigating distribution issues commonly encountered with single-point regulation systems.

L7805 Overview

Incorporating essential features such as internal current limiting, thermal shut-down, and safe area protection, the L7805 is built to be highly durable and reliable under typical operating conditions. With adequate heat sinking, it can deliver more than 1 ampere of output current, making it suitable for powering various electronic components. While primarily a fixed voltage regulator, it can be adapted with external components to achieve adjustable output voltages and currents, enhancing its versatility for diverse applications.


How to Use

To effectively use the L7805CV voltage regulator, ensure you connect a 0.33μF capacitor at the input and a 0.1μF capacitor at the output for stable operation. Input voltage should range between 7-35 volts, connected to the Vin pin (Pin 1). Ground the GND pin (Pin 2) and connect the output pin (Pin 3) to your circuit's positive supply rail for a regulated 5V output. To manage heat dissipation, use a heat sink or ensure proper ventilation. This approach ensures optimal performance and durability of the L7805CV in your projects.


Specifications & Features


  • Output Voltage: 5 V
  • Output Current: 1.5 A
  • Voltage - Input (Max): 35 V
  • Voltage - Output (Min/Fixed): 5 V
  • Voltage Dropout (Max): 2 V @ 1 A (Typ)
  • Current - Output: 1.5 A
  • Quiescent Current (Iq): 8 mA
  • Load Regulation: 100 mV
  • Line Regulation: 100 mV
  • PSRR / Ripple Rejection (Typ): 62 dB (120Hz)
  • Package / Case: TO-220, TO-220-3
  • Operating Temperature Range: 0°C to +125°C
  • Minimum Operating Temperature: 0°C
  • Maximum Operating Temperature: +125°C
  • Unit Weight: 0.056438 oz
  • Number of Regulators: 1
  • Protection Features: Over Temperature, Short Circuit



  • High Output Current Capability: Supports up to 1.5 A of output current.
  • Multiple Output Voltage Options: Available output voltages include 5V, 6V, 8V, 8.5V, 9V, 12V, 15V, 18V, and 24V.
  • Robust Thermal Protection: Integrated thermal overload protection ensures reliable operation under high-temperature conditions.
  • Enhanced Short Circuit Protection: Built-in short circuit protection for added safety and device longevity.
  • Safe Operating Area (SOA) Protection: Includes output transition SOA protection for stability and performance.
  • Precision Output Voltage: Achieves 2% output voltage tolerance in the "A" version.
  • Wide Operating Temperature Range: The "A" version is guaranteed to perform in extended temperature ranges for versatile application use.


L7805 Pinout

The L7805CV is a three-terminal positive voltage regulator that ensures a stable 5V output. Widely used in electronic circuits, it helps maintain a consistent power supply, safeguarding sensitive components from voltage fluctuations. Understanding its pinout configuration is crucial for effective utilization.

L7805 Pinout

L7805 Pinout Configuration


Pin Number

Pin Name



Input (Vin)

Connects to the unregulated input voltage, accepting a range from 7V to 35V. Ensure the input voltage is at least 2V higher than the output voltage for proper functionality.


Ground (GND)

Serves as the common ground of the circuit, providing a stable reference potential for the regulator's operation.


Output (Vout)

Delivers the regulated 5V output, connecting to the positive supply rail of the circuit to power various components.


Block Diagram


Block Diagram


Schematic Diagram

Schematic Diagram

L7805 Application

Power Supply for Microcontrollers:

The L7805 is commonly used to provide a stable 5V power supply for microcontrollers and microprocessor-based systems. It ensures that the microcontroller receives a consistent voltage, essential for reliable operation and to prevent malfunctions due to voltage fluctuations. For instance, in an Arduino-based project, the L7805 can be employed to regulate the input voltage to 5V, ensuring that the board operates correctly and consistently.


Regulated Power for Sensors:

Many sensors, such as temperature sensors, proximity sensors, and accelerometers, require a stable 5V power supply for accurate readings and reliable performance. The L7805 can be used to regulate the power supply to these sensors, ensuring they receive a constant voltage despite variations in the input power source. This application is crucial in precision measurement and data acquisition systems.


5V Power Supply for Digital Circuits:

Digital circuits, including logic gates, flip-flops, and memory devices, often require a stable 5V supply for proper operation. The L7805 can be used to provide this regulated voltage, ensuring that digital circuits function correctly without issues related to voltage instability. This application is commonly found in digital electronics and embedded systems.


Powering 5V Relays:

Relays are used to switch higher power loads with a lower control voltage. When using 5V relays, the L7805 can be employed to supply a stable 5V voltage to the relay coils. This application is typical in automation systems where relays are used to control various devices based on signals from microcontrollers or other logic circuits.


Voltage Regulation in Battery-Powered Devices:

In battery-powered devices, such as handheld gadgets and portable electronics, the L7805 can regulate the voltage from the battery to provide a consistent 5V output. This is particularly useful when the battery voltage can vary significantly as it discharges. The L7805 ensures that the device operates within its required voltage range, extending battery life and maintaining device functionality.


Power Supply for Communication Equipment:

Communication equipment, such as radios, modems, and network devices, often requires a stable 5V supply for proper operation and signal integrity. The L7805 can be used to regulate the voltage in these devices, ensuring that they operate reliably and maintain communication performance. This application is critical in maintaining the reliability and quality of communication systems.


L7805 Application Circuit


L7805 Application Circuit

Application Circuit - DC parameter

DC parameter


Application Circuit - Load regulation

Load regulation


Application Circuit - Ripple rejection

Ripple rejection


Advantages and Disadvantages of L7805


Advantages of L7805

  • Simplicity: Easy to use with minimal components.
  • Stable Output: Provides a consistent 5V voltage.
  • Thermal Protection: Includes thermal overload protection.
  • Short-Circuit Protection: Protects against short circuits.
  • Wide Input Range: Accepts input voltages from 7V to 35V.
  • Cost-Effective/Price: Inexpensive and affordable.


Disadvantages of L7805

  • Heat Dissipation: Can get hot and may need a heat sink.
  • Limited Output Current: Max output is around 1.5A.
  • High Dropout Voltage: Requires a significant difference between input and output voltage.
  • Fixed Output Voltage: Only provides a 5V output, not adjustable.
  • Lower Efficiency: Less efficient compared to switching regulators.


L7805 Equivalent Parts for Recommend


LM350 (adjustable)

LM338 (adjustable)





L7805 PDF Datasheet

Download L7805 datasheet pdf>>


Differences between LM317 and L7805

The LM317 and L7805 are both voltage regulators but serve different purposes. The L7805 is a fixed 5V linear regulator with a set output voltage, while the LM317 is an adjustable regulator that can be configured to output a range of voltages. The LM317 has a higher current capability and lower dropout voltage compared to the L7805. Additionally, the LM317 requires external resistors to set the output voltage, whereas the L7805 provides a fixed output without additional components.

Differences between LM317 and L7805





Output Voltage

Adjustable (1.25V to 37V)

Fixed 5V

Dropout Voltage

Lower (typically 1.5V)

Higher (typically 2V)

Current Capability

Up to 1.5A or more

Up to 1.5A


Requires external resistors

No adjustment needed

Package Types

Available in various packages

Typically TO-220 or similar


Flexible, configurable voltage

Fixed applications needing 5V



In summary, the L7805 voltage regulator is a valuable component for achieving a stable 5V output in electronic circuits. Its straightforward application, combined with essential protective features, makes it ideal for powering microcontrollers, sensors, digital circuits, relays, and communication equipment. While it offers a fixed voltage output with good performance, it is essential to consider its limitations, such as heat dissipation and dropout voltage, when designing circuits. The L7805's ability to provide reliable power supply solutions underscores its significance in electronic design, ensuring consistent operation and protection for various electronic devices and systems.

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  • What is the maximum output current of the L7805?

    The L7805 can typically supply up to 1.5A of output current.

  • What is the input voltage range for the L7805?

    The L7805 requires an input voltage range between 7V and 35V.

  • Why do I need capacitors with the L7805?

    Capacitors are needed for stable operation: a 0.33μF capacitor at the input and a 0.1μF capacitor at the output help reduce voltage ripples and improve transient response.

  • What is the dropout voltage of the L7805?

    The dropout voltage of the L7805 is typically around 2V, meaning the input voltage must be at least 2V higher than the output voltage.

  • Can the L7805 be used to regulate voltages other than 5V?

    No, the L7805 is designed specifically for a fixed 5V output. For other voltages, you would need a different regulator or an adjustable one like the LM317.

  • What should I do if the L7805 overheats?

    Ensure proper heat dissipation by using a heat sink or providing adequate ventilation. Excessive heat can lead to thermal shutdown or damage.

  • Can the L7805 be used in battery-powered devices?

    Yes, but the input voltage must be higher than the battery voltage by at least the dropout voltage to ensure proper regulation.

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