LM723CN Voltage Regulator: Pinout, Circuit and Applications

LM723CN Introduction

The LM723 is a monolithic integrated programmable voltage regulator, available in a 14-lead dual in-line plastic package and an SO-14 micro package. This versatile IC offers internal current limiting, providing reliable protection for connected circuits. When the output current surpasses 150mA, an external NPN or PNP pass transistor can be integrated to handle higher loads. Additionally, the LM723 features adjustable current limiting and remote shutdown functionality.

LM723CN Pinout

NC: No connection.

CURRENT LIMIT: Sets the current limit with an external resistor.

CURRENT SENSE: Monitors output current via a sensing resistor.

INVERTING INPUT: Inverting input for internal comparator; used for feedback.

NON-INVERTING INPUT: Non-inverting input for comparator; reference voltage comparison.

VREF: Provides stable internal reference voltage (approx. 7.15V).

V-: Connects to negative power supply or ground.

NC: No connection.

Vz: Sets Zener diode reference voltage for regulation.

Vout: Provides regulated output voltage.

Vc: Connects to frequency compensation network.

V+: Connects to positive power supply.

FREQUENCY COMPENSATION: Connects compensation network to stabilize regulator.

NC: No connection.

LM723CN Symbol

LM723CN Footprint 

LM723CN 3D Model

LM723CN Schematic Diagram

LM723CN Test Circuit

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LM723CN Specifications

Specification	Value
Type	Programmable Voltage Regulator
Package	14-lDIP
Voltage - Input (Max)	40V
Voltage - Output (Min/Fixed)	2V
Voltage - Output (Max)	37V
Current - Output	150mA
Current - Quiescent (Iq)	4 mA
Temperature Range	0°C ~ 70°C
Dropout Voltage	3V
Load Regulation	0.10%
PSRR	86db ~ 74dB (100Hz ~ 10kHz)
Frequency Compensation	External network required

LM723CN Features

Input Voltage Up to 40V

Output Voltage Adjustable From 2 to 37V

Positive or Negative Supply Operation

Series, Shunt, Switching or Floating Operation

Output Current to 150mA Without External Pass Transistor

ADJUSTABLE CURRENT LIMITING

LM723CN Applications

Power Supply Design

Battery Chargers

DC-DC Converters

Overvoltage and Overcurrent Protection

Linear Regulators

Lab Equipment and Test Instruments

Remote Shutdown Circuits

LM723CN Package

The LM723CN in 14-DIP packaging is a Dual In-line Package with 14 pins, commonly used in integrated circuits. This type of packaging is suitable for through-hole mounting and is typically used in voltage regulators and power supply circuits. The 14-DIP package offers advantages such as easy installation and maintenance, while providing secure mechanical connections in circuits. Each pin is neatly arranged on both sides of the package, making it convenient for insertion and soldering on prototype or circuit boards.

How to Use LM723CN?

Connect the LM723CN properly into the circuit. Pins 1, 8, and 14 are NC (not connected) and are not part of the circuit. Pin 12 should be connected to the positive terminal of the input power supply, and pin 7 to the negative terminal. Pin 6 provides the internal reference voltage and is used to set the regulator's output voltage, while pins 4 and 5 are the inverting and non-inverting inputs for feedback signals. By adjusting the current limit pin (pin 2), current control can be achieved, preventing overload.

Finally, test and fine-tune the circuit. After completing the connections, use a multimeter to measure the output voltage and current. If the output is not as expected, adjust the external components or feedback loop to optimize performance.

FAQs

What is LM723CN?

LM723CN is a programmable voltage regulator IC designed to provide stable output voltage with internal current limiting, ideal for power supply applications.

What are the typical applications of LM723CN?

LM723CN is commonly used in adjustable power supplies, voltage regulators, and battery chargers due to its programmable voltage and current limit features.

Does LM723CN include thermal protection?

No, LM723CN does not have built-in thermal protection. However, proper heat sinking and external circuitry can help manage thermal conditions.

What is the difference between LM723 and LM723CN?

The LM723CN is a plastic DIP package variant of the LM723, offering the same features but in a more commonly used package for prototyping and consumer applications.