REG1117A/2K5: The Ultra-Low Dropout Linear Regulator

Introduction

The REG1117A/2K5 is a high-performance, ultra-low dropout (LDO) linear regulator capable of providing a stable output voltage with very low dropout voltage. It is ideal for applications requiring a low-noise, high-efficiency power supply, such as portable devices, battery-powered systems, and sensitive analog circuits.

Features and Benefits

• Ultra-low dropout voltage: 1.3V typ. at 1A load
• Adjustable output voltage range: 1.25V to 13.8V
• High output current capability: 2A continuous output current
• Low quiescent current: 1mA typ. at 1mA load
• Stable with ceramic capacitors
• Short-circuit and thermal protection
• Compact SOT-223 package

Applications

The REG1117A/2K5 is suitable for a wide range of applications, including:

• Portable devices: smartphones, tablets, wearables
• Battery-powered systems: laptops, power tools, medical devices
• Sensitive analog circuits: audio amplifiers, RF transceivers, precision measurement equipment
• Low-noise power supplies: instrumentation, test equipment, medical imaging

Technical Specifications

Design Considerations

When using the REG1117A/2K5, it is important to consider the following design factors:

• Input voltage: The input voltage must be higher than the desired output voltage by at least the dropout voltage.
• Output capacitance: A minimum of 10μF of ceramic capacitance is required on the output for stability.
• Input capacitance: A 1μF ceramic capacitor is recommended on the input to improve transient response.
• Heat dissipation: The REG1117A/2K5 can dissipate up to 1.5W of power. If the device is operated at high current or high input-to-output voltage differential, a heatsink may be necessary.

Applications Circuit

The following figure shows a typical application circuit for the REG1117A/2K5:

[Image of the typical application circuit]

Tips and Tricks

• For best performance, use a low-ESR ceramic capacitor on the output.
• If the input-to-output voltage differential is high, consider using a heatsink to prevent thermal shutdown.
• For applications requiring very low noise, add a filter capacitor between the output and ground.
• To reduce quiescent current, use a smaller value for the output capacitor.

Step-by-Step Approach

To use the REG1117A/2K5 in a design, follow these steps:

1. Determine the desired output voltage and current requirements.
2. Select the appropriate output voltage version of the REG1117A/2K5.
3. Design the power supply circuit according to the datasheet specifications.
4. Test the circuit to verify its performance.

Conclusion

The REG1117A/2K5 is a versatile and high-performance ultra-low dropout linear regulator that is ideal for a wide range of applications. Its low dropout voltage, high output current capability, and low quiescent current make it an excellent choice for power-sensitive devices and battery-powered systems.