LM7805 Voltage Regulator Pinout, Application and Alternative

The LM7805 is one of the most recognizable and widely used voltage regulator ICs in electronics. Designed to deliver a stable +5V DC output from a higher input voltage, it has become a standard choice in power supply designs for decades. From simple DIY projects to industrial control circuits, the LM 7805 value for its reliability, ease of use, and built-in protection features.

As a member of the LM 7805 family of three-terminal positive voltage regulators, it integrates internal current limiting, thermal shutdown, and safe-area protection. These features allow it to operate safely under a wide range of conditions, often without the need for complex external circuitry. With proper heat dissipation, it can supply significant output current, making it suitable for both analog and digital applications where require a clean and dependable 5V rail.

1. LM7805 Overview

2. LM7805 Pinout and Configurations, CAD Models

3. LM7805 Voltage Regulator Specifications

4. LM7805 Voltage Regulator Applications

5. LM7805 Functional Equivalents

6. LM7805 vs LM2596

7. LM7805 Alternative

8. 7805 Regulator Features

9. LM7805 Module

10. Frequently Asked Questions

LM7805 Overview

The LM 7805 is one of the most widely used linear voltage regulator ICs, designed to provide a fixed +5V DC output from a higher DC input voltage.

These regulators employ internal current limiting, thermal shutdown, and safe-area compensation, making them essentially indestructible under normal operating conditions. With adequate heat sinking, the 7805 can deliver output currents exceeding 1.5A, making it suitable for a wide range of low-power and medium-power applications.

The chip primarily intend for use as a fixed voltage regulator, especially in local (on-card) regulation. This approach helps eliminate noise and voltage drop issues associated with single-point regulation. In addition to fixed regulation, the LM 7805 can also configure with external components to achieve adjustable output voltages and current regulation.

A major design goal of the LM 7805 family was ease of use. Only require a minimal number of external components for stable operation. Output bypass capacitors are not mandatory, although they improve transient response. Typically require input bypassing only when the regulator locate far from the main filter capacitor of the power supply.

For applications requiring tighter accuracy and improved electrical performance, a higher-grade version known as LM340A is available.

LM7805 Pinout and Configurations, CAD Models

The LM 7805 is a 3-pin linear regulator, and its pinout is consistent across most packages.

LM7805 Pin Configuration

LM7805 Voltage Regulator Circuit Diagram

CAD Models

LM7805 Voltage Regulator Specifications

Common Manufacturers

The circuit produce by many semiconductor vendors, including:

Fairchild (ON Semiconductor)

STMicroelectronics (ST)

Texas Instruments (TI)

Electrical specifications remain largely compatible across manufacturers, though minor differences exist.

LM7805 Package Dimensions (Typical)

LM7805 Voltage Regulator Applications

The 7805 series integrates thermal protection, output short-circuit protection, and output transistor safe-area protection. Despite these safeguards, still require careful design to prevent excessive power dissipation and overheating.

Common Applications

· +5V regulated power supplies

· Microcontroller and logic IC power rails

· Sensor and analog circuit biasing

· Educational and laboratory power supplies

LM7805 as a +5V Voltage Regulator

In its most common configuration, the 7805 provides a fixed +5V output using only minimal external components. This makes it ideal for powering digital ICs such as microcontrollers, logic gates, and communication modules.

LM7805 as an Adjustable Output Regulator

By adding resistors or diodes between the ground-pin and system-ground, the 7805 can configure to provide output voltages higher than 5V, although this approach is less flexible than using a dedicated adjustable regulator like the LM317.

LM7805 Functional Equivalents

Several compatible devices offer similar electrical performance and pin compatibility.

Note:
These parts are generally pin-compatible 7805 alternatives, but electrical characteristics, accuracy, and thermal performance vary slightly by manufacturer.

LM7805 vs LM2596

Summary:
The LM 7805 is ideal for simple, low-noise +5V regulation where efficiency is not critical. In contrast, the LM2596 is a buck switching regulator IC that offers adjustable output voltage, higher current capability, and much better efficiency, making it suitable for power-hungry or battery-powered applications.

LM7805 Alternative

Can use several voltage regulators as alternatives to the 7805, depending on the required output voltage, current rating, polarity, and efficiency.

Note:
When selecting an 7805 alternative, always verify output voltage, current capability, dropout voltage, and package type to ensure compatibility with the target application and thermal design.

7805 Regulator Features

Output Current: Up to 1.5 A (with adequate heat sinking)

Voltage Options: Available in fixed 5V, 12V, and 15V versions

Output Voltage Tolerance: ±2% at TJ = 25°C (LM340A version)

Internal Protections: Thermal overload, short-circuit, and safe operating area (SOA) protection

Package Options: Available in space-saving SOT-223, TO-220, TO-3, TO-263

Stability: Output capacitance not required for stable operation

Note:
These features make the 7805 series highly reliable and easy to use for fixed voltage regulation in a wide range of electronic applications.

LM7805 Module

LM7805 7805 Three-terminal Voltage Regulator Module 5V Regulated Power Supply PCB Board

The module is a compact power supply board designed to provide a stable 5V output with continuous current capability, making it ideal for DIY, experimental, and small-scale electronics applications.

Key Features:

3A Bridge Rectifier: Supports both AC and DC input, with no polarity concern, allowing continuous high-current output.

High-Quality Filtering: Equipped with two 35V 220µF electrolytic capacitors to stabilize and smooth the output voltage.

1.5A High-Current Regulator Chip: Ensures reliable continuous output of large current.

Enhanced Heat Dissipation: Includes a heat sink plate to improve thermal performance.

Versatile Applications: Suitable for DIY power supplies, monitoring systems, experimental setups, camera power, vehicle electronics, and communication equipment.

Lightweight and Portable: Compact design allows easy installation anywhere.

Technical Specifications:

· Input Voltage: 7.5 – 20V (AC or DC, no polarity)

· Output Voltage: 5V regulated

· Peak Output Current: 1.2A

· Load Regulation: 100 mV

· Static Current: 8 mA

· Output Noise Voltage: 42 µV

· Input-Output Voltage Difference: 2V

· Output Impedance: 15 mΩ

· Board Size: 57 × 23 mm

This module integrates full-wave rectification, filtering, and regulation in a compact PCB, making it a convenient solution for stable 5V power in a variety of electronics projects.

Applications:
DIY power supplies, monitoring systems, laboratory supplies, camera power, vehicle electronics, and communication equipment.

Frequently Asked Questions

What is the difference between LM317 and LM7805?

The LM317 is an adjustable positive voltage regulator that allows output voltages from 1.25V to 37V using external resistors. The LM7805 is a fixed +5V linear regulator with no adjustment. LM317 offers flexibility, while LM 7805 provides simplicity and easy 5V regulation.

What is the maximum output current of LM7805?

The 7805 can deliver a maximum output current of 1.5A when properly heat-sinked. Exceeding this without adequate cooling may trigger thermal shutdown, reducing reliability. Continuous operation at high current requires attention to thermal dissipation to prevent overheating and maintain stable voltage regulation.

How to test LM7805 with multimeter?

To test an LM7805, connect the input pin to a DC voltage >7V, ground pin to common ground, and measure the output pin with a multimeter. A properly working LM7805 should read close to +5V. Recommend no load or minimal load testing for safety.

What is LM7805 price?

The LM7805 is a low-cost and widely available voltage regulator, typically priced around $0.20 to $2 per piece, depending on package type, manufacturer, and quantity. Bulk purchases or sourcing from local electronics suppliers can reduce costs further, making it an economical solution for DIY and industrial projects.

Is LM7805 a MOSFET?

No, the LM7805 is not a MOSFET. A linear voltage regulator IC based on bipolar junction transistor (BJT) technology. The internal series pass transistor controls current flow to maintain a stable output voltage rather than functioning as a discrete MOSFET switch.

What is LM in LM7805?

The prefix “LM” in LM7805 originates from National Semiconductor and stands for “Linear Monolithic.” It denotes that the IC is a monolithic linear regulator, integrating all necessary circuitry, including reference, amplifier, and series pass transistor, into a single chip for simplified voltage regulation.

What does 7805 stand for?

In LM7805, “78” indicates a positive voltage regulator series, and “05” specifies the fixed output voltage of +5V. Together, 7805 identifies a standard linear IC designed to provide a regulated +5V output with built-in protections and standard pin configuration.

How many pins does LM7805 have?

The LM7805 has three pins: Input (V+), Ground (GND), and Output (Vo). This 3-terminal design is standard for the 78xx series, allowing simple connection in power supply circuits while providing internal protection features such as thermal shutdown, short-circuit protection, and safe-area operation.

Conclusion:

The LM7805 remains a popular choice for reliable +5V regulation because its simplicity, robustness, and wide availability. Despite the rise of switching regulators, it continues to be a practical solution for low-noise and straightforward power supply designs.

Read More:

1. LM317T Voltage Regulator: Pinout, Datasheet and Equivalent

2. Guide To The AMS1117 Voltage Regulator

3. LM2576 Voltage Regulator – Feature, Pinout and Applications