L7908ACV

Introduction

The L7908ACV is an adjustable linear voltage regulator which ensures that a particular voltage level is maintained even with varying input voltages and load conditions. It is designed and manufactured by STMicroelectronics and belongs to the L79xx family of regulators. The device is available in 1.2V to 37V output voltage range and is suitable for applications such as battery chargers, portable equipment, notebook computers, game consoles, and set-top boxes.

Architechture and Features

The L7908ACV integrates a wide range of features for efficient, cost-effective and reliable operation. One of its features is the variable output voltage of up to 37V which can be adjusted using two resistors connected to the adjustment terminals located at pin 8 and 9. The device includes an on/off feature which allows it to be switched off when the input voltage is too low or the output voltage too high. This feature helps in conserving power and protecting the load from potential damage.

The L7908ACV offers a low dropout (LDO) voltage which is adjustable from 2.5V to 37V while its quiescent current is only 8.5mA at full load. Other features include short-circuit protection and thermal shutdown which help prevent damage to the regulator circuitry in the event of overload or short circuit. The device also incorporates a wide range of protection functions such as over-temperature protection, reverse voltage protection, output over-current protection, etc.

Applications and Working Principle

The L7908ACV is designed to provide a constant voltage source to a variety of applications. It can be used in portable devices, cellular phones, computers and other implementations. It is also used in automotive and industrial applications. The output voltage is adjustable from 2.5V to 37V using two separate resistors. Typical applications include battery charging, DC-to-DC converters, high efficiency switching regulators, and lighting control systems.

The working principle of the L7908ACV is based on that of an ideal linear regulator, which is a three-terminal device composed of an input, output, and ground terminals, along with the necessary NPN transistors. When the input voltage is greater than the output voltage, the transistor acts as a switch to divert the excess power. Thus, the output voltage is maintained at the specified level. The device is capable of dissipating up to 150mW, making it extremely efficient when compared to other types of voltage regulators.

Conclusion

The L7908ACV is a reliable and cost effective adjustable linear voltage regulator designed and manufactured by STMicroelectronics. Key features include an adjustable output voltage, low quiescent current, wide input and output voltage range, short-circuit protection, output over-current protection, reverse voltage protection, and thermal protection. Typical applications includes battery chargers, portable equipment, computer systems, automotive, and other high efficiency switching systems.