LDOs for Noise-Free PowerRails > 자유게시판

 

In modern electronic components warehouse designs, ensuring the integrity of the signal chain is crucial and one of the key considerations is the noise caused by the power supply needs to be minimized. Low Drop Out (LDOs) are often used to provide a clean, low-noise power rail for sensitive circuits, and their applications extend from simple low-power systems to high-performance digital systems.

What are LDOs?

 LDOs are a type of voltage regulator designed to provide a stable output voltage while consuming minimum power. Unlike traditional linear regulators, LDOs operate with a small differential between the input and output voltages, reducing power waste and heat generation. This characteristic makes LDOs an attractive choice for applications where power consumption is a critical consideration.

Noise in Electrical Systems 

Noise in power supplies can compromise the performance of even the most sophisticated electronic systems. It can manifest as AC ripple, corrupting signals, altering data, and potentially causing system failures. High-quality power rails are essential for maintaining signal integrity and ensuring reliable system operation.

Characteristics of Good LDOs

When selecting an LDO for a low-noise power rail, several key characteristics should be considered:

1. Low Dropout Voltage: A low dropout voltage ensures that the regulator consumes minimal power and generates minimal heat.
   
2. Rejecting AC Noise: Power supply rejection ratio (PSRR) measures the LDO's ability to reject switching noise from the input voltage. A high PSRR value indicates that the LDO can effectively reject noise and maintain a clean output.
   
3. Low Noise Density: Noise density measures the amount of noise generated by the LDO. A low noise density value indicates that the LDO is noise-free.
   
4. Setting a Wide Range of Voltages: The ability to set a wide range of output voltages allows designers to tailor the power rail to specific application requirements.
   
5. Robust Power Supply: A high output current capacity ensures that the LDO can supply power to critical circuits without compromising performance.
   
   

Implementation Considerations 

To ensure optimal performance from an LDO, several implementation considerations must be taken into account:

1. Bypassing: Proper bypassing of the input capacitor to the LDO is essential to maintain high signal integrity.
   
2. Short and Wide Wires: To minimize inductance and radiation, keep the LDO's input and output wires as short and wide as possible.
   
3. Grounding: A proper grounding scheme is crucial to prevent ground loops.
   
   

By selecting an LDO with the right characteristics and implementing it correctly, designers can create robust, low-noise power rails that will support critical applications.