LM138K datasheet by STMicroelectronics

LM138K Frequently Asked Questions (FAQs)

• What is the maximum input voltage that the LM138K can handle?
  The LM138K can handle input voltages up to 35V, but it's recommended to keep it below 25V for optimal performance and to prevent overheating.
• How do I ensure the LM138K is stable and doesn't oscillate?
  To ensure stability, make sure to use a minimum output capacitance of 10uF, and a maximum ESR (Equivalent Series Resistance) of 5 ohms. Also, keep the input and output capacitors close to the regulator to minimize parasitic inductance.
• What is the minimum input voltage required for the LM138K to regulate properly?
  The LM138K requires a minimum input voltage of 2V above the output voltage to regulate properly. For example, if you're using the 5V version, the input voltage should be at least 7V.
• Can I use the LM138K in a high-temperature environment?
  The LM138K is rated for operation up to 125°C, but its performance may degrade at high temperatures. Make sure to derate the output current and input voltage according to the datasheet's thermal derating curves.
• How do I protect the LM138K from input voltage transients and spikes?
  Use a TVS (Transient Voltage Suppressor) diode or a voltage clamp circuit at the input to protect the LM138K from voltage transients and spikes. This will help prevent damage to the regulator and ensure reliable operation.