MIC5281YMME

MIC5281YMME Application Field and Working Principle

The MIC5281YMME is a low-dropout (LDO) linear voltage regulator, developed by Micrel and offered in both surface-mount and through-hole packages. Built on a complementary bipolar process and incorporating micropower features, this LDO regulator is an improved version of the earlier MIC5281 series, offering better operation temperature, lower quiescent current, and higher output voltage. The device established a new level of ultra-low dropout voltage and low quiescent current performance in the LDO industry.

Features and Benefits

This linear voltage regulator offers a wide range of benefits for a variety of electronic applications, including:

• Ultra-low dropout voltage and low quiescent current;
• Wide input voltage range from 2.5V to 5.5V;
• Very low operating current: less than 19µA;
• Smoothing capacitor for noise reduction;
• Over-temperature and short-circuit protection.

Applications

The MIC5281YMME is typically used in a variety of applications, including but not limited to:

• Bluetooth® audio amplifiers;
• Portable multi-media devices;
• Mobile telephones;
• Portable audio equipment;
• Set-top boxes;
• Small displays and hand-held electronic products

Working Principle

The MIC5281YMME is a low dropout linear voltage regulator, meaning it can regulate a voltage much closer to the input voltage than a switching regulator. This is achieved by using a transistor that is held in the transition region (the linear region) which acts as a current source.

The circuit topology of the MIC5281YMME is a floating source type (FST) controlled by a bandgap reference voltage. A voltage divider is used to set the output voltage, and a feedback loop provides the necessary control to keep the output voltage stable. The current flowing through the series control transistor is proportional to its base bias, which in turn is regulated by the voltage error signal.

In operation, the voltage error signal at the feedback node is used to adjust the base current of the series control transistor so that the output remains close to its set point. This keeps the output regulated even with input voltage and output current fluctuations.

The MIC5281YMME is designed to provide high power output with very low quiescent current. The device operates from an input voltage range of 2.5V to 5.5V, and offers an adjustable output voltage range of 1.8V to 5.5V.

In addition, the device has built-in thermal and short-circuit protection. When these conditions occur, the device automatically shuts down and prevents any further damage to the connected circuitry.

Conclusion

Overall, the MIC5281YMME is an ideal choice for portable and battery powered applications, offering superior performance and low power consumption. With its wide input and output voltage range, low operating current, and built-in protection features, it is an excellent choice for many electronic projects.