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The LM317S is an adjustable 3-terminal linear voltage regulator that can output a voltage range from 1.25V to 37V with a maximum output current of 1.5A. It is commonly used in power supplies and is noted for its ability to provide a stable output voltage regardless of variations in input voltage and load conditions. Functions - Voltage Regulation: Regulates output voltage to a fixed or adjustable level. - Current Regulation: Can be configured to limit output current for safety. - Thermal Protection: Built-in thermal overload protection prevents damage under excessive load conditions. - Short Circuit Protection: Offers short-circuit protection to safeguard the device. Applications - Power Supplies: Used in applications where adjustable voltage is needed, such as in linear power supplies. - Battery Chargers: Can be used for charging batteries due to its adjustable output. - LED Drivers: Suitable for powering LED circuits requiring a specific voltage. - Test Equipment: Employed in laboratory power supplies and test equipment where precise voltage control is necessary. Alternative Parts 1. LM317T: Similar to the LM317S but with slightly different packaging options. 2. LM338: Offers higher output current capability (up to 5A) while having a similar adjustable voltage range. 3. LM1117: A low dropout adjustable voltage regulator that can provide similar functionality with a smaller footprint. 4. LT1086: Low dropout adjustable voltage regulator featuring a 1.5A output current. Embedded Modules - LM317 Modules: Pre-assembled regulator modules that utilize the LM317S, typically featuring variable resistors for easy adjustment of output voltage. These modules often come with additional components that enhance usability. Related Q&A 1. Q: What input voltage range does the LM317S support? A: The LM317S can accept an input voltage range of 3V above the desired output voltage up to a maximum of 40V. 2. Q: How do you adjust the output voltage of an LM317S? A: The output voltage of the LM317S is adjusted using two external resistors, configured as a voltage divider. The output voltage can be calculated using the formula \(V_{out} = V_{ref} \times \left(1 + \frac{R2}{R1}\right) + I_{adj} \times R2\), where \(V_{ref}\) is typically 1.25V. 3. Q: What are the thermal limits of the LM317S? A: The LM317S has a thermal shutdown feature that activates if the junction temperature exceeds 125°C, protecting the device from overheating. 4. Q: Can the LM317S be used for high current applications? A: The LM317S can output a maximum of 1.5A; however, for applications requiring higher currents, alternatives like the LM338 or other higher current regulators are recommended. 5. Q: Is the LM317S suitable for use in battery-powered devices? A: Yes, the LM317S can be used in battery-powered devices, as long as the input and output voltage requirements are met and the circuit is designed to accommodate the dropout voltage and current needs.