LM2676S-5.0 Application Field and Working Principle

The LM2676S-5.0 are step-down Switched Mode Power Supplies (SMPSs) designed to provide up to 1A of output current to meet a variety of utility and industrial applications. The LM2676S-5.0 are available in adjustable and fixed output voltage options, with a wide input voltage range of 4.5-60V. These step-down, synchronous PWM SMPS ICs are designed using National Semiconductor\'s MultiSim isolated SIMEX-Lite process, which allow them to offer high efficiency and minimal ripple and noise. This makes them ideal for low-noise, low-current applications, such as those requiring adjustable output voltages between 8-36V, as well as for input voltage requirements up to 60V.The LM2676S-5.0 features an internal fixed-frequency PWM oscillator, with user-controllable switching frequencies. The small switching ripple and low noise are obtained through the use of a low-resistance synchronous rectifying MOSFET, coupled with a highly efficient switching converter and output voltage compensation. Additionally, the device includes a wide-range remote-on/off control input and frequency synchronization, as well as built-in protection against overvoltage, overcurrent, over-temperature, and overload conditions.The LM2676S-5.0 offer a wide range of features suitable for a variety of applications, including - but not limited to - power-supply designs using step-down converters, as well as applications requiring multiple output voltages, such as servers, disk drives, automotive systems, audio amplifiers, and other industrial applications.

Working Principle

The LM2676S-5.0 are Pulse Width Modulated (PWM) switching regulators, which are used for voltage regulation and current limiting. The PWM action of the LM2676S-5.0 is based on controlling the width of the switching pulses. The width of the pulses is regulated such that the average voltage across the load is equal to the desired output voltage. The PWM module uses an internal voltage reference and an error amplifier whose output is compared with the output of the voltage reference. If the error amplifier output is higher than the reference voltage, the output switch is turned on for a longer period until the required output voltage is achieved. This process is repeated until a stable output voltage is set.

Features and Benefits

The LM2676S-5.0 are designed to offer exceptional performance in a low-current, low-noise environment. These PMICs offer many benefits, including:

• Wide input voltage range of 4.5-60V
• Output current up to 1A
• User-controllable switching frequencies
• Low-resistance Synchronous Rectifier MOSFET
• Wide-range remote-on/off control input and frequency synchronization
• Built-in protection against overvoltage, overcurrent, over-temperature, and overload conditions
• High efficiency and minimal ripple and noise
• Ideal for a variety of applications, such as audio amplifiers, automotive systems, servers, and disk drives.

Conclusion

The LM2676S-5.0 offer a variety of features and benefits for SMPS designs that require wide-input voltage range, adjustable or fixed output voltage, and a low-current, low-noise operation. The device is used for a variety of applications, making it suitable for many utility and industrial applications. The compact, 5-pin offering provides a high level of integration and cost-efficient for a wide range of design requirements.