The LDL1117S33R from STMicroelectronics is a linear voltage regulator capable of delivering up to 1.2 A of output current. It operates with an input voltage range from 2.5 V to 18 V, making it versatile for various applications. A notable feature of this component is its low dropout voltage, typically 350 mV at full load (1.2 A), which allows for efficient operation even when the input-to-output voltage differential is minimal.
This device exhibits a high power supply rejection ratio (PSRR) of 87 dB at 120 Hz, decreasing to over 40 dB at 100 kHz, which is particularly beneficial for applications requiring stable voltage under varying load conditions. The LDL1117S33R incorporates several protection features, including current limit, Safe Operating Area (SOA) protection, and thermal protection, enhancing its reliability in diverse operating environments. Its operating temperature range extends from -40 °C to 125 °C, packaged in a SOT223 format, suitable for compact designs.
Voltage Regulators
Low-dropout (LDO) voltage regulators are electronic components designed to provide a stable output voltage with a minimal difference between the input and output voltages. These regulators are essential in applications where the power supply voltage is only slightly higher than the required voltage of the circuit, making efficiency and thermal performance critical considerations.
LDOs are widely used in battery-powered devices, where extending battery life is important, and in applications requiring low noise and stable power supply, such as sensitive analog circuits and RF systems. When selecting an LDO, engineers should consider key parameters such as dropout voltage, output current capacity, power supply rejection ratio (PSRR), and the thermal performance of the device.
The dropout voltage is particularly important as it determines the minimum input-to-output voltage differential at which the regulator can maintain a stable output. A lower dropout voltage results in more efficient power usage. The output current capacity should match or exceed the maximum current demand of the load to ensure reliable operation.
PSRR is a measure of how well the LDO can reject variations in the input voltage, ensuring a stable output even under fluctuating input conditions. Lastly, thermal performance is crucial for maintaining operational integrity and preventing damage from overheating, especially in high-current applications.
In summary, LDO voltage regulators are crucial for providing stable, efficient power in a wide range of electronic devices. Their selection and application require careful consideration of electrical and thermal characteristics to meet the specific needs of the application.