LD1117V18

Overview

The LD1117V18 is a positive low dropout voltage regulator manufactured by STMicroelectronics, designed to deliver up to 950 mA of output current. It provides a fixed 1.8 V output with a typical dropout voltage of 1 V and a maximum of 1.1 V. The device operates within an input voltage range of 3.3 V to 15 V and maintains a supply voltage rejection ratio of 75 dB. It features internal thermal and current limiting protections, ensuring stability with a minimum 10 μF output capacitor. The unit is housed in a TO-220-3 through-hole package, suitable for applications requiring robust power management.

Feature Summary

• Fixed 1.8 V output voltage with ±1% tolerance at 25 °C
• Internal thermal overload and short-circuit current protection
• High efficiency NPN pass transistor design
• Requires only a standard 10 μF output capacitor for stability

Applications

• Battery-powered systems requiring efficient linear regulation
• Post-regulation stages for switching mode power supplies
• General-purpose power supply circuits
• Embedded system logic level translation

Procurement Notes

Verify the specific suffix and package configuration against the official datasheet before procurement, as variations exist within the LD1117 family. Confirm that the required output current and thermal dissipation capabilities align with the TO-220-3 package limitations. Ensure the application circuit includes the necessary input and output capacitors to maintain stability and prevent oscillation under all operating conditions.

Selection Notes

Select this component when a fixed 1.8 V rail is needed with high current capability. The TO-220-3 package offers superior thermal performance compared to surface-mount options, making it suitable for higher power dissipation scenarios. Verify that the input voltage remains within the specified 3.3 V to 15 V range to ensure proper regulation and avoid excessive power loss or device damage.

Part Context

This part belongs to the LD1117 series of adjustable and fixed low-dropout positive voltage regulators. The series is characterized by its ability to provide up to 800 mA to 950 mA of output current while maintaining a low dropout voltage. It is widely used in applications where noise-sensitive circuits require clean power from unregulated or switching sources.

Replacement Considerations

Check for pin-compatible alternatives such as other manufacturers' LDOs offering similar 1.8 V fixed outputs and current ratings. Ensure any substitute matches the TO-220-3 package dimensions and thermal characteristics. Verify that the replacement device meets the same input voltage range and stability requirements regarding output capacitance.