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Using the LM723 Voltage Regulator for Reliable Power Regulation

The LM723 is a versatile voltage regulator that offers reliable, adjustable power regulation for various electronic applications. This guide will walk you through its features, applications, and setup options to help you get the best performance out of your circuit.

Catalog

[IMAGE OF LM723]

Overview of LM723

The LM723 is a versatile, programmable voltage regulator designed with flexibility in mind. It’s built as a monolithic integrated circuit in a 14-lead dual-in-line plastic and SO-14 micro package, making it adaptable for various applications. Inside, it offers a reliable current-limiting function. If the output current surpasses 150mA, you can incorporate an external NPN or PNP transistor to handle higher loads effectively. The LM723 also allows for adjustable current limits, meaning it can be tailored to specific requirements, including remote shutdown capabilities. This adaptability and robust design make the LM723 a dependable choice for different voltage regulation needs.

LM723 Pin Configuration

[IMAGE OF LM723 Pin Configuration]

LM723 CAD Model

LM723 Symbol

[IMAGE OF LM723 Symbol]

LM723 Footprint

[IMAGE OF LM723 Footprint]

LM723 3D Model

[IMAGE OF LM723 3D Model]

LM723 Features

Adjustable Voltage Range

You can set the output voltage of the LM723 between 2V and 37V, allowing flexibility to meet specific voltage needs for various applications. This range makes it suitable for both low and high voltage regulation setups.

High Input Voltage Capacity

With a maximum input voltage of 40V, the LM723 can handle relatively high voltage levels, which adds versatility to its usage in different circuit designs where higher input voltages are required.

Output Current Flexibility

The LM723 provides an output current of up to 150mA on its own, but by adding an external pass transistor, you can boost this capacity to handle up to 10A. This feature expands its applications to circuits with larger power requirements.

Low Standby Current

The IC is designed with low standby current consumption, reducing power waste when it’s idle. This feature makes it a more efficient choice for applications where energy-saving is a priority.

High Ripple Rejection

The LM723 is built to offer high ripple rejection, which means it minimizes fluctuations in output voltage caused by variations in input. This results in a more stable and consistent output, crucial for sensitive applications.

Temperature Stability

Designed to operate within -55°C to +125°C, the LM723 maintains reliable performance across a wide temperature range. This allows it to be used in both standard and demanding environments without affecting output stability.

Fold-Back Current Limiting

The IC includes fold-back current limiting, which automatically reduces the output current if the load increases beyond a safe level. This feature helps protect both the IC and the connected circuit from damage due to excessive current.

LM723 Schematic Diagram

[IMAGE OF LM723 Schematic]

LM723 Specifications

Technical specifications, features, characteristics, and components with comparable specifications of STMicroelectronics LM723N.

[TABLE OF Specifications]

Applications of LM723

Low and High Voltage Regulators

With the LM723, you can create both low (2V to 7V) and high voltage (7V to 37V) regulators by adjusting the external components accordingly. This makes it suitable for powering various types of electronic devices with specific voltage needs.

Linear and Switching Regulators

The LM723 functions well as either a linear or switching regulator, providing stable voltage regulation for both types of power supply circuits. This adaptability makes it a practical choice for different types of regulated power supplies.

Floating Regulators

The IC also works effectively as a floating regulator, where it controls the voltage difference rather than a fixed ground reference. This application is especially useful in designs requiring isolated or independent power supplies.

Series and Shunt Regulators

The LM723 can be configured as both series and shunt regulators, expanding its usability in diverse circuit setups. Series regulators are commonly used for higher current needs, while shunt regulators are ideal for low-power applications.

LM723 Application Circuit Examples

Basic Low Voltage Regulator (VO = 2 to 7V)

[IMAGE OF LM723 Simple Application Circuit]

Basic High Voltage Regulator (VO = 7 to 37V)

[IMAGE OF LM723 Simple Application Circuit-1]

Equivalents of LM723

• MC1723CP

• LM723N

• LM723CN

• LM723CMX

• LM723QML

Usage of LM723 in Circuits

LM723 finds practical use in applications requiring an adjustable voltage regulator, suitable for shunt, current, and temperature control. By adding an external transistor, you can achieve higher output voltage and current levels, even up to 10A. With its extended temperature range, this IC performs consistently across various environments, adding to its reliability. Whether as a linear or switching regulator, LM723 is well-suited for configurations that call for stable voltage control. The IC is especially effective in series regulator applications, where it ensures stable voltage with minimized output variation, giving you precise control over your circuit.

Configuring LM723 for Desired Voltage Output

To achieve different output voltage ranges with this IC, refer to the various circuit configurations provided in the LM723 datasheet that suit your specific voltage requirements. For example, to set an output voltage between 2V and 7V, you can use the Basic Voltage Regulator circuit shown below, utilizing the LM723 voltage regulator.

[IMAGE OF LM723 Circuit]

To calculate the resistance value for R3, use this formula:

R3 = (R1 * R2) / (R1 + R2)

You can adjust the output voltage by fine-tuning the potentiometer in the circuit. To determine the output voltage for this setup, apply the formula:

Vout = Vref * (R2 / (R1 + R2))

LM723 Package Information

[IMAGE OF LM723 Package]

Manufacturer of LM723

STMicroelectronics, established in 1987, is a globally recognized leader in electronics and semiconductor manufacturing. Headquartered in Geneva, Switzerland, it leads in semiconductor innovation across Europe, consistently advancing technology in various applications.

Frequently Asked Questions [FAQ]

1. What is an LM723?

The LM723 is a programmable voltage regulator designed as a monolithic integrated circuit. It comes in a 14-lead dual-in-line plastic and SO-14 micro package. This IC includes built-in current limiting, and if the output current goes above 150mA, an external NPN or PNP transistor can be added. It also allows for adjustable current limits and has a remote shut-down feature.

2. What are the advantages and disadvantages of the LM723?

The LM723 has several advantages, including low noise, a wide voltage range, support for external pass transistors, user-adjustable compensation, flexibility, availability across the full temperature range, and cost-effectiveness.

However, it also has some drawbacks, such as limited accuracy in current limiting, sensitivity to overload conditions, a relatively high dropout voltage, and moderate gain in the error amplifier. Using MOSFET pass transistors with it requires careful handling.

3. What is the operating temperature range of the LM723?

The LM723 operates reliably in temperatures from -55°C to 125°C.

4. How does the LM723 work?

The LM723 regulates voltage by taking an input voltage at PIN12, which it then adjusts to provide a stable output voltage at PIN6. A feedback loop, using a resistor and capacitor, connects to the IC's non-inverting pin, allowing the IC to compare voltages at the inverting and non-inverting pins and maintain the output voltage within the set parameters.

5. What are common applications of the LM723?

The LM723 is mainly used in series voltage regulator circuits but can serve as both positive and negative voltage regulators. It can deliver up to 150mA of current to a load, with the potential to handle over 10A by adding external power transistors.

6. What is a voltage regulator?

A voltage regulator is an electronic device that keeps the output voltage of a power source within a certain range. It ensures that connected electrical equipment receives a steady voltage, preventing damage or malfunction due to voltage fluctuations.

7. What is the output voltage range of the LM723?

The LM723 circuit can provide a regulated output voltage ranging from 7V to 37V, with a maximum load current of 150mA.