LD1117S12TR

Overview

The LD1117S12TR is a fixed-output low-dropout linear voltage regulator manufactured by STMicroelectronics. It provides a fixed output voltage of 1.2 V with a maximum output current capability of 800 mA. The device operates within an input voltage range up to 15 V and features a typical dropout voltage of 1 V at full load. It incorporates internal thermal overload protection and current limiting. The component is housed in a SOT-223 surface-mount package, suitable for applications requiring efficient power management in compact designs.

Feature Summary

• Fixed 1.2 V output voltage with high efficiency due to NPN pass transistor design
• Integrated thermal overload and short-circuit current limiting protection
• Low quiescent current consumption optimized for battery-powered systems
• Requires only a minimal 10 μF output capacitor for stability

Applications

• Battery-powered consumer electronics requiring stable low-voltage rails
• Post-regulation stages for switching power supplies
• Portable equipment with space-constrained PCB layouts
• Embedded systems needing precise fixed voltage references

Procurement Notes

Verify the specific suffix 'S12' confirms the 1.2 V fixed output variant, as the LD1117 family includes multiple voltage options. Confirm the 'TR' suffix indicates tape-and-reel packaging if automated assembly is required. Ensure the SOT-223 package matches the target footprint. Cross-reference the manufacturer part number with official STMicroelectronics documentation to validate authenticity and revision status before procurement.

Selection Notes

Select this component when a stable 1.2 V rail is required with up to 800 mA load current. The SOT-223 package offers a balance between thermal performance and board space savings compared to larger packages. Consider the input-to-output voltage differential to ensure the dropout voltage specifications are met under all operating conditions. Verify that the thermal dissipation capabilities of the chosen PCB layout can handle the expected power loss.

Part Context

This component belongs to the LD1117 series of low-dropout positive voltage regulators from STMicroelectronics. The series is designed to provide high efficiency and tight output voltage tolerance. Other variants in the family offer different fixed output voltages (1.8 V, 2.5 V, 3.3 V, 5.0 V) or an adjustable version. The SOT-223 package is one of several available form factors, including DPAK and TO-220, catering to various thermal and spatial requirements.

Replacement Considerations

Direct pin-compatible replacements within the same family include other LD1117xx variants with different fixed output voltages, provided the system voltage requirement changes. For identical 1.2 V output, verify cross-reference data sheets for equivalent LDOs with matching current ratings and package dimensions. Ensure any substitute maintains similar dropout characteristics and protection features.